Method for synthesizing epothilones and epothilone analogs

ABSTRACT

A method for making epothilones and epothilone analogs is described, as are novel compounds made by the method. One embodiment of the method was used to synthesize epothilone B by a convergent approach that entailed Wittig coupling of an ylide derived from phosphonium bromide with an aldehyde. The former was prepared from propargyl alcohol by a nine-step pathway which installed both trisubstituted double bonds with clean Z configuration. Macrolactonization of a resulting seco acid provided the following intermediate diene epothilone analog. Selective saturation of the 9,10-olefin and subsequent epoxidation provided epothilone B.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of prior copending U.S.patent application Ser. No. 09/499,596, which is incorporated herein byreference.

FIELD

The present invention concerns a method for making epothilones andepothilone analogs, and compounds made by the method.

BACKGROUND I. INTRODUCTION

Epothilones A (2) and B (4) were discovered by Höfle and coworkers whileexamining metabolites of the cellulose-degrading myxobacterium Sorangiumcellulosum (Myxococcales) as potential antifungal agents. Höfle, G.;Bedorf, N.; Gerth, H.; Reichenbach (GBF), DE-B 4138042, 1993 (Chem.Abstr. 1993, 120, 52841). Höfle, G.; Bedorf, N.; Steinmeth, H.;Schomburg, D.; Gerth. H.; Reichenbach, H. Angew. Chem. Int. Ed. Engl.1996, 35, 1567.

Initial investigations by scientists at the Gesellschaft fürBiotechnologische Forschung in Germany concerned the action ofepothilones against fungi, bacteria, and a variety of animal cell lines.Höfle, G. et al., Chem. Abstr., 1993, 120, 52841. The epothilones testedhad only a narrow spectrum of antifungal activity, but had a ratherdramatic effect against oomycetes, such as Phytophotora infestans, thecausative species of potato-blight disease. Nicolaou, K. C. et al.,“Chemical Biology of Epothilones,” Angew. Chem. Int. Ed., 1998, 37,2015, which is incorporated herein by reference.

Although the antifungal spectrum of 2 and 4 proved to be quite narrow,scientists at Merck found that these macrolides are highly cytotoxic.Bollag, D. M.; McQueney, P. A.; Zhu, J.; Hensens, O.; Koupal, L.;Liesch, J.; Goetz, M.; Lazarides, E.; Woods, C. M. Cancer Res. 1995, 55,2325. The epothilones had powerful activity against mouse fibroblast andleukemia cells (2 ng mL⁻¹) and strong immunosuppressive activity. Gerth,K., et al., Antibiot., 1996, 49, 560-563. By observing the effect of theepothilones on induction of tubulin polymerization to microtubules andnoting that 2 and 4 are competitive inhibitors of Taxol with almostidentical IC₅₀ values, it was concluded that epothilones act at thecellular level by a mechanism similar to Taxol. Bollag, D. M. Exp. Opin.Invest. Drugs 1997, 6, 867; Nicolaou, et al., Angew. Chem. Int. Ed.Engl., supra. Epothilone B (2) was particularly impressive in theseassays, having a 2,000-5,000-fold higher potency than Taxol inmultiple-drug-resistant cell lines. Bollag, D. M.; et al., Cancer Res.1995, supra.

After scientists from Merck reported their findings on the mode ofaction of epothilones in 1995, interest in these compounds increased.The Merck scientists subjected tens-of-thousands of compounds tobiological assays for Taxol-like tubulin-polymerization activity. Theironly hits were epothilones A and B.

II. TUBULIN AND MICROTUBULES

Tubulin polymerization-depolymerization plays an important role in thecell cycle, particularly during mitosis. Tubulin is a heterodimerprotein comprising globular α,β-tubulin subunits. Tubulin is themonomeric building block of microtubules. Microtubules are one of thefundamental structural components of the cytoskeleton in all eukaryoticcells. Microtubules help develop and maintain the shape and structure ofthe cell as needed. They may operate alone, or in conjunction with otherproteins to form more complex structures, such as cilia, centrioles, orflagella. Nicolaou et al., at 2019, supra.

Structurally, microtubules are regular, intemetworked linear polymers(protofilaments) of highly dynamic assemblies of heterodimers of α and βtubulin. Nicolaou et al., supra. When thirteen of these protofilamentsare arranged parallel to a cylindrical axis they self-assemble to formmicrotubes. These polymers form tubes of approximately 24 nm in diameterand up to several μm in length. Nicolaou et al., supra.

The growth and dissolution of microtubules are regulated by bound GTPmolecules. During polymerization, GTP molecules hydrolyze to guanosinediphosphate (GDP) and orthophosphate (Pi). The half-life of tubulin at37° C. is nearly a full day, but that of a given microtubule may be only10 minutes. Consequently, microtubules are in a constant state of fluxto respond to the needs of the cell. Microtubule growth is promoted in adividing or moving cell, but is more controlled in a stable, polarizedcell. The regulatory control is exerted by adding (for growth) orhydrolyzing (for shrinkage) GTP on the ends of the microtubule.

Microtubules are major components of the cellular apparatus and play acrucial role in mitosis, the process during cell replication in whichthe duplicated genetic material in the form of chromosomes ispartitioned equally between two daughter cells. When cells entermitosis, the cytoskeletal microtubule network (mitotic spindle) isdismantled by melting at the center, and two dipolar, spindle-shapedarrays of microtubules are formed outwards from the centrosome. Nicolaouet al., at 2020, supra. In vertebrate cells, the centrosome is theprimary site of microtubule nucleation (microtubule-organizing center orMTOC). At metaphase, the dynamic action of the microtubules assemblesthe chromosomes into an equatorial position on the mitotic spindle. Atanaphase, the microtubule dynamics change and the chromosomes partitionand move to the new spindle poles on the dynamic microtubules, where thenew cells are being formed. Nicolaou et al., supra. By this process, theparent cell duplicates its chromosomes, which provides each of the twodaughter cells with a complete set of genes. When it is time for aeukaryotic cell to divide, microtubules pull its chromosomes apart andpushes them into the two emerging daughter cells. The rate at whichmicrotubules change their length increases by 20- to 100-fold duringmitosis relative to the rate during interphase. These rapid dynamics aresensitive to tubulin-interactive agents which exert their antimitoticaction at the metaphase-to-anaphase transition. Kirschner et al., Cell,1986, 45, 329-342.

III. ANTICANCER DRUGS THAT DISRUPT MICROTUBULE DYNAMICS

A number of anticancer drugs having diverse molecular structures arecytotoxic because they disrupt microtubule dynamics. Most of thesecompounds, including known chemotherapeutic agents colchicine, colcemid,podophyllotoxin, vinblastine, and vincristine, interfere with theformation and growth of microtubules and prevent the polymerization ofmicrotubules by diverting tubulin into other aggregates. This inhibitscell proliferation at mitosis.

Vinblastine binds to the ends of microtubules. Vinblastine's potentcytotoxicity appears to be due to a relatively small number ofend-binding molecules. Mitchison et al., Nature, 1984, 312, 237-242.

Colchicine first binds to free tubulin to form complexes. Thesecomplexes are incorporated into the microtubules at the growth ends inrelatively low concentrations, but show profound effects on themicrotubule dynamics. Toso R. J., Biochemistry, 1993, 32, 1285-1293.

Taxol disturbs the polymerization-depolymerization dynamics ofmicrotubules in vitro, by binding to the polymeric microtubules andstabilizing them against depolymerization. Cell death is the net result.Epothilones appear to act by the same mechanism and bind to the samegeneral-regions as Taxol does. Bollag et al., Cancer Res., 1995, 55,2325-2333. Epothilones displace Taxol from its receptor, but bind in aslightly different manner to microtubules, as suggested by their actionagainst Taxol-resistant tumor cells, which contain mutated tubulin. Eachtubulin molecule of the microtubules contains a Taxol binding site.Taxol and epothilone binding markedly reduce the rate of α/β tubulindissociation.

Merck scientists compared the effects of the epothilones and Taxol ontubulin and microtubules and reported higher potencies for bothepothilones A and B as tubulin polymerization agents (epothiloneB>epothilone A>Taxol). All three compounds compete for the same bindingsite within their target protein. The epothilones exhibit similarkinetics in their induction of tubulin polymerization, and gave rise tomicroscopic pictures of stabilized microtubules and damaged cells thatwere essentially identical to those obtained with Taxol. Epothilones aresuperior to Taxol as killers of tumor cells, particularly multiple drugresistant (MDR) cell lines, including a number resistant to Taxol. Insome of the cytotoxicity experiments, epothilone B demonstrated a2,000-5,000-fold higher potency than Taxol, as stated above. Moreover,in vivo experiments, carried out recently at Sloan Kettering in N.Y.involving subcutaneous implantations of tumor tissues in mice, provedthe superiority of epothilone B.

On treatment with epothilones B, cells appear to be in disarray withtheir nuclei fragmented in irregular shapes and the tubulin aggregatedin distinct wedge-shaped bundles. By interacting with tubulin, theepothilones block nuclear division and kill the cell by initiatingapoptosis.

Recently, Hamel and co-workers examined the actions of epothilones A andB with additional colon and ovarian carcinoma cell lines and comparedthem with the action of Taxol. Kowalski R. J., et al., J. Biol. Chem.,1997, 272, 2534-2541. Pgp-overexpressing MDR colon carcinoma lines SW620and Taxol-resistant ovarian tumor cell line KBV-1 retainedsusceptibility to the epothilones. With Potorous tridactylis kidneyepithelial (PtK2) cells, examined by indirect immunoflourescence,epothilone B proved to be the most active, inducing extensive formationof microtubule bundles. Nicolaou et al., at 2022, supra.

Epothilone A initiates apoptosis in neuroblastoma cells just as Taxoldoes. Unlike Taxol, epothilone A is active against a Pgp-expressing MDRneuroblastoma cell line (SK—N—SH). And, the efficacy of epothilone wasnot diminished despite the increase of the Pgp level duringadministration of the drug.

IV. TAXOL SIDE EFFECTS

Taxol molecules bind to microtubules, making cell division impossible,which kills the cells as they begin to divide. Since cancer cells dividemore frequently than healthy cells, Taxol damages tumors where runawaycell division occurs most profoundly. Other rapidly dividing cells, suchas white blood cells and hair cells, also can be attacked. Consequently,side effects are experienced by patients taking the drug. Chemotherapywith Taxol frequently is accompanied by immune system suppression,deadening of sensory nerves, nausea, and hair loss (neutropenia,peripheral neuropathy, and alopecia).

Taxol exhibits endotoxin-like properties by activating macrophages,which in turn synthesize proinflammatory cytokines and nitric oxide.Epothilone B, despite its similarities to Taxol in its effects onmicrotubules, lacked any IFN-γ-treated murine-macrophage stimulatoryactivity as measured by nitric oxide release, nor did it inhibit nitricoxide production. Epothilone-mediated microtubule stabilization does nottrigger endotoxin-signaling pathways, which may translate in clinicaladvantages for the epothilones over Taxol in terms of side effects.

The importance of the epothilones as therapeutic agents recently wasdiscussed on the front page of the Jan. 27, 2,000 edition of the WallStreet Journal. This article states:

-   -   But Taxol has its drawbacks. Some fast-dividing cancer cells can        mutate into forms resistant to the drug. Often, patients with        advanced cancer who respond at first to Taxol don't respond        after several cycles of treatment because their cells become        resistant, too. Despite conducting dozens of trials over the        years, Bristol-Myers has been frustrated in its efforts to        expand Taxol's effectiveness beyond certain breast, ovarian and        lung cancers.    -   That's why the new drugs, broadly classified as part of a family        of chemicals known as the epothilones, hold such promise. In        studies not yet published, Bristol-Myers and others have shown        that the epothilones disrupt cell division through the same        biochemical pathway as Taxol. But for reasons scientists are        only beginning to understand, the new drugs are equally        effective against cancer cells already resistant to Taxol, as        well as cells that develop resistance over time.

V. SYNTHESES OF EPOTHILONES

Based on the biological activity of the epothilones and their potentialas antineoplastics, it will be apparent that there is a need for anefficient method for making epothilones and epothilone analogs. Fourtotal syntheses of 4, and several incomplete approaches, are known. See,for example: (1) Nicolaou, K. C.; Ninkovic, S.; Sarabia, F.; Vourloumis,D.; He, Y.; Vallberg, H.; Finlay, M. R. V.; Yang, Z. J. Am. Chem. Soc.1997, 119, 7974; (2) Meng, D.; Bertinato, P.; Balog, A.; Su, D.-S.;Kamenecka, T.; Sorensen, E. J.; Danishefsky, S. J. J. Am. Chem. Soc.1997, 119, 10073; (3) May, S. A.; Grieco, P. Chem. Commun. 1998, 1597;(4) Schinzer, D.; Bauer, A.; Schieber, J. Synlett 1998, 861; (5) Mulzer,J.; Mantoulidis, A. Tetrahedron Lett. 1996, 37, 9179; (6) Claus, E.;Pahl, A.; Jones, P. G.; Meyer, H. M.; Kalesse, M. Tetrahedron Lett.1997, 38, 1359; (7) Gabriel, T.; Wessjohann, L. Tetrahedron Lett. 1997,38, 1363; (8) Taylor, R. E.; Haley, J. D. Tetrahedron Lett. 1997, 38,2061; (9) Brabander, J. D.; Rosset, S.; Bernardinelli, G. Synlett 1997,824; (10) Chakraborty, J. K.; Dutta, S. Tetrahedron Lett. 1998, 39, 101;(11) Liu, Z.-Y.; Yu, C.-Z.; Yang, J. D. Synlett 1997, 1383; (12) Liu,Z.-Y.; Yu, C.-Z; Wang, R.-F.; Li, G. Tetrahedron Lett. 1998, 39, 5261;(13) Mulzer, J.; Mantoulidis, A.; Öhler, E. Tetrahedron Lett. 1997, 38,7725; and (13) Bijoy, P.; Avery, M. A. Tetrahedron Lett. 1998, 39 1209.

Methods for making epothilone and epothilone analogs also have beendescribed in the patent literature, including: (1) Schinzer et al., WO98/08849, entitled “Method for Producing Epothilones, and IntermediateProducts Obtained During the Production Process”; and (2) Reichanbach etal., WO 98/22461, entitled “Epothilone C, D, E, and F, ProductionProcess, and Their Use as Cytostatic as well as Phytosanitary Agents.”One disadvantage associated with these prior processes for synthesizingepothilones is the lack of stereoselectivity in the production of the Ztrisubstituted bond of the desepoxyepothilone. As a result, a newsynthetic approach to epothilones and epothilone analogs is requiredwhich addresses this and other problems associated with syntheses of theepothilones known prior to the present invention.

SUMMARY

The present invention provides a novel method for making epothilones andepothilone analogs. The method can provide almost completestereoselectivity with respect to producing the Z trisubstituted doublebond of the desepoxyepothilone, and therefore addresses one of thedisadvantages associated with methods known prior to the presentinvention.

One embodiment of the method comprises first providing a compound havingFormula 1.

With reference to Formula, 1 R is H or a protecting group; R₁ is an arylgroup, such as, without limitation, benzene derivatives or the thiazoleof epothilone B; R₂—R₅ substituents independently are selected from thegroup consisting of H and lower alkyl groups; and R₆ substituentsindependently are selected from the group consisting of lower alkylgroups. Compounds having Formula 1 are then converted into an epothiloneor an epothilone analog. For example, in the synthesis of epothilone Bthe step of converting the compound can involve first removing theprotecting groups, and thereafter forming an epoxide at C-12, C-13.

In preferred embodiments, R₁ is the thiazole shown below.

Most known epothilones have this thiazole as the aryl group.

Providing compounds having Formula 1 can be accomplished in a number ofways. One embodiment comprises coupling a first compound having Formula2,

where R is H or a protecting group and X is a functional group orchemical moiety equivalent to a carbanion at a terminal carbon of thefirst compound, with a second compound having Formula 3

With reference to Formula 3, R₂ is H or lower alkyl, R₃ is H or aprotecting group, and Y is an electrophillic group capable of reactingwith and coupling to the terminal carbon of the first compound. Theprecursor compound is then converted into compounds having Formula 1.For example, two compounds, one having Formula 2 and the other Formula3, can be coupled by a Wittig reaction where X is PPH₃ ⁺ and Y is acarbonyl compound, such as an aldehyde.

Compounds having Formula 1 can be provided by a second embodiment of thepresent invention. This second embodiment involves coupling a firstcompound having Formula 4

where R is H or a protecting group and X is a halide, with a secondalkyne compound having Formula 5

where R₁ is H or a protecting group and R₂ is H or lower alkyl. Thiscompound is then converted into a compound having Formula 1. This secondembodiment can proceed by first forming an enyne precursor compoundhaving Formula 6

where the substituents are as stated above.

Still another embodiment of the method of the present invention forforming epothilones or epothilone analogs comprises forming theprecursor enyne compound having Formula 6 where R₁ is H or a protectinggroup, or a triene compound having Formula 7

where R₁ is H or a protecting group, R₂ is H or lower alkyl, and R₃ is Hor a protecting group. Compounds having Formulas 6 and/or 7 are thenconverted into a compound having Formula 8, where the carbon atomnumbers correspond to the numbering system stated for epothilone A.

With reference to Formula 8, R—R₇ are independently selected from thegroup consisting of H, lower aliphatic groups, particularly lower alkylgroups, protecting groups, or are bonded to an O in an epoxide or anaziridine. More particularly, R substituents independently are H, loweralkyl, or a protecting group; R₁ is an aryl group; R₂ is H or loweralkyl; C₁₃ and C₁₂ are carbons bonded together by a single bond or adouble bond; R₃ and R₄ independently are H, lower aliphatic groups, orare bonded to O in an epoxide or to N in an aziridine; C₁₀ and C₉ arecarbons in a double bond or triple bond, and, where C₁₀ and C₉ arecarbons in a double bond, R₅ and R₆ independently are H, or loweraliphatic; and R₇ substituents independently are selected from the groupconsisting of lower aliphatic groups. The configuration of the doublebond between C₁₀ and C₉ may be cis or trans or E or Z. Compounds havingFormula 8 are then converted into an epothilone or an epothilone analog.Moreover, the compound having Formula 6 may be converted into thecompound having Formula 7, such as by catalytic semi-hydrogenation.Lindlar's catalyst has proven an effective catalyst for conducting thiscatalytic semi-hydrogenation.

The method of the present invention differs from other pathways byassembling the macrolide from two segments, which first are connected atC-9, C-10 before macrolactonization. With reference to the firstembodiment of the present invention, fragments were constructed around apreformed Z trisubstituted alkene to circumvent stereochemical problemsafflicting known synthetic methods. The 9,10 olefin produced by couplingthe two segments confers rigidity on the one portion of the epothilonemacrocycle that exhibits flexibility, and hence may be expected toimpact its tubulin binding properties. Moreover, this alkene provides achemical moiety from which novel epothilone analogues can be prepared.

Epothilones, such as epothilone A, epothilone B, epothilone C,epothilone D, epothilone E, and epothilone F, can be made by the methodof the present invention. The present invention also provides novelcompounds that can be made by the method. These compounds typically haveFormula 8

where the substituents are as described above. Preferred compoundssatisfying Formula 8 include one or more of the following: (1) R beinghydrogen; (2) R₁ being the aryl thiazole side chain of the epothilones;(3) R₂ being hydrogen or methyl; (4) R₃—R₆ being hydrogen or methyl, orR₃ and R₄ and/or R₅ and R₆ being bonded to oxygen in an epoxide; (5) R₇being methyl.

Compounds having Formula 8 include several chiral centers, which allowsfor a plurality of diastereomers. The present invention is directed toall such stereoisomers. But, the epothilones have knownstereochemistries at each of the chiral centers. As a result, preferredcompounds of the present invention have the same stereochemistries ateach chiral center as do the epothilones. This is illustrated below inFormula 9, which shows the stereochemistries of preferred epothiloneanalogs at each chiral center.

DETAILED DESCRIPTION

The process of the present invention can be used to make knownepothilones A, B, C, D, E and F, as well as analogs of these compounds,including the cryptothilones, which typically are dilactone orlactone-amide-type analogs of the epothilones. The cryptothilones arehybrid structures which include a portion of cryptophycins and a portionof the epothilones. One such novel diene analog 10 has double bonds atpositions C-9, C-10, and C-12, C-13, including all combinations of cis(10) and trans (11) (Z and E) double bonds

Using compound 10 and/or 11 to make analogs of epothilones, such as thecryptothilones, provides advantages relative to prior known syntheses,as indicated above.

A method for making diene 10 and converting 10 into, for example,epothilone B, as well as other epothilones and epothilone analogs, isdescribed below.

I. EPOTHILONE STRUCTURES AND EPOTHILONE ANALOGS

Formula 8 is a generic structural formula for diene and enynederivatives of Compound 10.

Preferred compounds have the stereochemistries shown in Formula 9.

With reference to Formulas 8 and 8, R is H, lower aliphatic, preferablylower alkyl, or a protecting group; R₁ is an aryl group; C₁₃ and C₁₂ arecarbons bonded together by a single or double bond; R₃ and R₄independently are H, lower alkyl, or are bonded to oxygen in an epoxideor to nitrogen in an aziridine; C₁₀ and C₉ are carbons in a single bond,double bond or triple bond, with preferred compounds having C₁₀ and C₉bonded together by a double bond or a triple bond; if C₁₀ and C₉ arebonded together by a double bond, the configuration of the double bondmay be cis or trans or E or Z; and R₅ and R₆ independently are H, loweraliphatic, preferably lower alkyl, or are bonded to heteroatoms incyclic structures, such as to oxygen in an epoxide or to nitrogen in anaziridine.

As used herein, “lower” refers to carbon chains having 10 or fewercarbon atoms, typically less than 5 carbon atoms. “Lower aliphatic”includes carbon chains having: (a) sites of unsaturation, e.g., alkenyland alkynyl structures; (b) non-carbon atoms, particularly heteroatoms,such as oxygen and nitrogen; and (c) all branched-chain derivatives andstereoisomers.

The phrase “protecting group” is known to those of ordinary skill in theart of chemical synthesis. “Protecting group” refers generally to achemical compound that easily and efficiently couples to a functionalgroup, and can be easily and efficiently removed to regenerate theoriginal functional group. By coupling a protecting group to a firstfunctional group of a compound other functional groups can undergochemical or stereochemical transformation without affecting thechemistry and/or stereochemistry of the first functional group. Manyprotecting groups are known and most are designed to be coupled to onlyone or a limited number of functional groups, or are used for particularcircumstances, such as reaction conditions. Theodora Greene's ProtectingGroups in Organic Syntheses, (Wilely Science, 1984), and later editions,all of which are incorporated herein by reference, discuss protectinggroups commonly used in organic syntheses. Examples of protecting groupsused to protect hydroxyl functional groups for the syntheses ofepothilones and epothilone analogs include the silyl ethers, such ast-butyl dimethyl silyl (TBDMS) ethers, and tetrahydropyranyl (THP)ethers.

“Aryl” refers to compounds derived from compounds having aromaticproperties, such as benzene. “Aryl” as used herein also includescompounds derived from heteroaromatic compounds, such as oxazoles,imidazoles, and thiazoles.

Preferred aryl groups have Formula 10

where X and Y are independently selected from the group consisting ofheteroatoms, particularly oxygen, nitrogen and sulfur. For theepothilones, and most epothilone analogs, the R₁ aryl group is thiazole18 shown below.

C₁₃ and C₁₂ of Formula 8 are carbons bonded together by a single ordouble bond. Whether C₁₃ and C₁₂ are joined by a single or double bonddetermines, in part, substituents R₃ and R₄. For example, if C₁₃ and C₁₂are coupled by a single bond, then R₃ and R₄ are selected from the groupconsisting of hydrogen and lower alkyl. Moreover, if C₁₃ and C₁₂ arecoupled by a single bond then R₃ and R₄ can be bonded to a heteroatom,such as oxygen and nitrogen, in a cyclic structure, such as an epoxideor an aziridine. Epoxide 20 and aziridine 22 are examples of thesecompounds.

Wavy and straight bonds to carbons at chiral centers of these structuresindicate that all stereoisomers are within the scope of the presentinvention. With respect to the aziridine analogs, such as aziridine 22,R₂ is selected from the group consisting of hydrogen, lower aliphatic,particularly lower alkyl, acyl, and aryl. Preferred compounds have R₂ behydrogen or lower alkyl.

C₁₀ and C₉ of Formula 8 are carbons bonded together by a single, doubleor triple bond. Whether C₁₀ and C₉ are joined by a single bond, a doublebond or a triple bond determines, in part, substituents R₅ and R₆. Forexample, if C₁₀ and C₉ are coupled by a single bond, then R₅ and R₆typically are selected from the group consisting of hydrogen and loweraliphatic, preferably lower alkyl. Moreover, if C₁₀ and C₉ are coupledby a single bond then R₅ and R₆ also can be bonded to a heteroatom, suchas oxygen and nitrogen, in a cyclic structure, such as an epoxide or anaziridine. Epoxide 24 and aziridine 26 provide examples of thesecompounds.

Compounds 28, 30, 32 and 34 provide additional examples ofepoxide/aziridine epothilone analogs.

II. BIOLOGICAL ACTIVITY

Known epothilones have significant biological activity. Novel epothiloneanalogs made according to the present invention also have been shown tohave significant biological activity. For example Table 1 providesbiological data for certain epothilones and epothilone analogs. TABLE 1IC₅₀ KB-31 IC₅₀ IC₅₀ IC₅₀ IC₅₀ IC₅₀ Tubulin (Epi- KB-8511 A549 HCT-116PC3-M MCF-7 Compound Poly.^(a) dermoid)^(b) (Epidermoid)^(b,c)(lung)^(b) (colon)^(b) (prostate)^(b) (breast)^(b)

95 0.17 0.16 0.16 0.34 0.32 0.29

88 1.94 1.00 4.62 4.48 7.40 2.31

56 59.39 28.54 109.03 101.83 146.47 72.00

36 103.70 70.37 109.27 109.97 146.80 95.03 Paclitaxel (Taxol) 53 2.67841.80 5.19 4.88 6.62 3.26^(a)Tubulin polymerization data (induction of porcine tubulinpolymerization) are for 5 μM compound concentration relative to theeffect of Epothilone B at a concentration of 25 μM, which is defined as100%.^(b)IC₅₀ values are expressed in nM and represent the mean of threeindependent experiments.^(c)KB8511 is a Pgp-overexpressing sub-line of the KB-31 line.

The antiproliferative activity of cis 9,10-dehydroepothilone D and trans9,10-dehydroepothilone D was assessed in vitro using a panel of humancancer cell lines. As illustrated in Table 1, cis 9,10-dehydroepothilonewas 20- to 30-fold less potent than natural epothilone D, and 330- to670-fold less potent than epothilone B. Interestingly, trans9,10-dehydroepothilone D showed biological activity very similar to thatof its cis isomer in spite of an apparent difference in the conformationof these two macrolactones. Thus, the average IC₅₀ of trans9,10-dehydroepothilone D for growth inhibition in the cell line panelused in this study was only 1.36-fold higher than that observed for cis9,10-dehydroepothilone D. As noted for epothilones B and D, cis9,10-dehydroepothilone D and trans 9,10-dehydroepothilone D retain fullanti-proliferative activity against KB-8511 cells, apaclitaxel-resistant cell line overexpressing P-glycoprotein (Table 1).While the tubulin polymerization activity of cis 9,10-dehydroepothiloneD and trans 9,10-dehydroepothilone D was lower than of naturalepothilone D (56%, 36%, and 88%, respectively) (Table 1), it isconceivable that decreased cellular penetration may contribute to thereduction in antiproliferative potency observed for cis9,10-dehydroepothilone D and trans 9,10-dehydroepothilone D. The absenceof a clear difference in the biological profiles of cis and transanalogues of 9,10-dehydroepothilone D observed here has a parallel inresults previously reported for other epothilone analogs. Thus,epothilones incorporating a trans epoxide or trans olefin at C12-C13have been shown to possess biological activity comparable to their cisisomer.

Taken together, these data support the proposition that the C8-C13region of the epothilone perimeter is relatively tolerant of structuralmodification and suggest that the interaction of this segment of themolecule with tubulin is less stringently defined.

III. METHOD FOR MAKING EPOTHILONES

The synthesis of epothilones can be exemplified by a working embodimentof a method for making epothilone B. Epothilone B was synthesized bycoupling a first subunit with a second subunit to form a coupledintermediate for forming epothilones. One embodiment of the methodcomprised coupling a first subunit 36 with a second subunit 38.

A second embodiment comprised coupling a first allylic halide subunit 40with a second alkyne subunit 42

With respect to 36, 38, 40, and 42, the R substituents are as describedabove.

A first embodiment of a the present method for making epothilones andepothilone analogs comprised making a suitable subunit 36 as illustratedby Scheme 1, i.e., compound 60.

Synthesis of segment 36 began from (Z)-3-iodo-2-methyl-2-propen-1-olprepared in geometrically pure form from propargyl alcohol. Afterprotection to provide 44, the iodoalkene was converted to thecorresponding cuprate, which underwent clean conjugate addition to(S)-3-acryloyl-4-benzyl-2-oxazolidinone (45) to yield 46. Hydroxylationof the sodium enolate derived from 46 with Davis oxaziridine gave 48.(See, for example, Evans et. al., Chem. Int. Ed Engl., Vol. 26, p. 2117,1997). The configuration of 48 was confirmed by oxidative degradation todimethyl (S)-malate. Protection of alcohol 48 as silyl ether 50,followed by exposure to catalytic potassium thioethoxide in ethanethiolprovided 52, along with recovered oxazolidinone (93%). Treatment ofthioester 52 with lithium dimethylcuprate furnished ketone 54, whichupon Horner-Emmons condensation with phosphonate 53 (shown below)produced

diene 56 in excellent yield, accompanied by 5% of its (Z,Z) isomer. Thetetrahydropyranyl ether protecting group was removed using magnesiumbromide. The liberated alcohol was converted to bromide 58. Homologationof 58 to phosphonium bromide 60 using triphenylmethylenephosphoranecompleted the synthesis of segment 36.

One embodiment of a segment 38, i.e., compound 74, was made as shown byScheme 2.

A key construction in one embodiment of a suitable segment 36 involvedan aldol condensation of ketone 62 with aldehyde 64. This doublestereodifferentiating reaction proceeded in good yield to giveanti-Felkin product 66 as the sole stereoisomer. An importantcontribution to the stereoselectivity of this condensation is made bythe p-methoxybenzyl (PMB) ether of 64, since the TBS protected versionof this aldehyde resulted only in a 3:2 mixture of 66 and its Felkindiastereomer, respectively. The favorable outcome with 64 is consistentwith chelation of the aldehyde carboxyl with both the lithium enolatefrom 62 and the PMB ether. After protection of 66 as tris ether 68, theterminal olefin was cleaved oxidatively to carboxylic acid 70, which wasconverted to its methyl ester 72. Hydrogenolysis of the PMB ether andoxidation of the resultant alcohol 74 yielded aldehyde 76.

Subunits 60 and 76 were coupled together, followed bymacrolactonization, to provide the diene lactone precursor to epothiloneB as shown below in Scheme 3.

Wittig coupling of the ylide from 58, compound 60, with aldehyde 76 atlow temperature afforded triene 78 as a single stereoisomer in excellentyield. Selective removal of the C-15 silyl ether of 78 was unsuccessful.But, after saponification to carboxylic acid 80 this deprotection wasreadily accomplished with tetra-n-butylammonium fluoride.Macrolactonization of seco acid 82 was carried out under Yamaguchi'sconditions and both silyl ethers were cleaved with acid to yield9,10-dehydrodes-epoxyepothilone B 84.

Compounds made in this manner can be converted to epothilones usingconventional chemistry. For example selective hydrogenation of thedisubstituted olefin of 84 with diimide gave the known lactone 86.Lactone 86 underwent epoxidation with dimethyldioxirane to produce 4.Epoxidation can be accomplished according to the method of Danishefskyet al., Angew. Chem., 1997, 109, 775; and Angew. Chem. Int. Ed. Engl.,1997, 36, 757, both of which are incorporated herein by reference.Characterization data for both 86 and 4 matched those in the literatureand/or of the naturally occurring product. The ¹H NMR spectrum of 4 wasin excellent agreement with that provided by Professor Grieco.

Schemes 1-3 provide a convergent synthesis of epothilone B (2), whichgenerates all seven of its asymmetric centers in a completelystereoselective fashion. In addition, clean Z configuration at the C-12,C-13double bond is incorporated by this pathway. Finally, the Z olefinat C-9, C-10 provides a chemical moiety from which exploratorystructural modifications can be made.

Scheme 4 illustrates a second embodiment of a method for makingepothilones and epothilone analogs.

With reference to Scheme 4, compound 76 was made as illustrated above inScheme 2, and as discussed in more detail in Example 16. Aldehyde 76 wasreacted with dimethyl diazophosphonate [J. C. Gilbert et al., J. Org.Chem., 1982, 47, 1837] in THF at −78° C. to provide alkyne 88 inapproximately 80% yield. The copper (I) derivative of alkyne 88 wasproduced and was found to couple with allylic halide 58. This reactionwas extensively investigated, and was found to proceed to product 90best when the conditions for the reaction were as shown in Table 2,using about 5% CuI, Et₃N, Et₂O-DMF, and about 2.0 equivalents of 88.Conditions investigated for this coupling are summarized below in Table4. TABLE 4 Equivalents Reagents/ of 86 Coupled With Conditions ProductYield 1.1 Allylic Halide 56 5% CuI, TBAB, K₂CO₃, DMF 8 1.1 AllylicHalide 56 20% CuI, ALIQUOT 336, 11 K₂CO₃, DMF 1.1 Allylic Halide 56 50%CuI, Pyrrolidine, DMF 0 1.1 Allylic mesylate of 54 (a) Ms₂O, Et₃N, DMF34 (b) 10% CuI, Na₂CO₃, TBAB, DMF 1.1 Allylic mesylate of 54 (a) Ms₂O,Et₃N, CH₂Cl₂ 42 (b) 20% CuI, Na₂CO₃, TBAB, DMF 1.1 Allylic Halide 56 5%CuI, Et₃N, Et₂O-DMF 24 2.0 Allylic Halide 56 5% CuI, Et₃N, Et₂O-DMF 60

Product 90 was semi-hydrogenated over Lindlar's catalyst [Pd/CaCO₃,Pd(OAc)₂]. This reaction was found to proceed best when hexanes was usedas the solvent. The hydrogenated product was then saponified using NaOHand isopropyl alcohol at 45° C. to provide the corresponding seco acid80 in approximately 66% yield. The C-15 TBS ether 80 was thendeprotected using TBAF and THF by warming the reaction from 0° C. to 25°C., with a yield of about 89%. The selectivity of this reaction isattributed to sterically favorable transilyation involving thecarboxylate anion. The resultant silyl ester is hydrolyzed duringaqueous work-up. Macrolactonization was then performed under Yamaguchiconditions. Yamaguchi et al., Bull Chem. Soc. Jpn, 1970, 52, 1989. Theremaining TBS ether protecting groups were then removed usingtrifluoroacetic acid (TFA) in dichloromethane at 0° C. to providecompound 84. Compound 84 was then converted to 4 as discussed withrespect to Scheme 3 and Examples 21, 22 and 23.

Schemes 5, 6, and 7 illustrate an embodiment of a synthesis via Stillecoupling that yields epothilone derivatives containing a trans (or E)double bond between C₉ and C₁₀ (See Formula 8).

With reference to Scheme 5, compound 92 was esterified with2-(trimethylsilyl)ethanol using Mitsunobu conditions to provide 94.Hydrogenolysis removed the p-methoxybenzyl ether from 94, and oxidationof alcohol 96 afforded an aldehyde which was reacted with Bestmann'sreagent (Müller et al., Synlett, p. 521, 1996) to give terminal alkyne96. Hydrostannylation of the latter in the presence of a palladiumdichloride catalyst furnished vinylstannane 98.

With reference to Scheme 6, compound 100, which was protected as TESether 102 with triethylsilyl triflate. The latter was advanced toalcohol 104 by a four-step sequence analogous to that used for theconversion of 48 to 56 (see Scheme 1) and including a final step ofremoving the tetrahydropyranyl ether protecting group with magnesiumbromide. For Stille coupling purposes, the allylic chloride 106 derivedfrom 104 was found to be more effective than the corresponding bromide(Scheme 1).

Coupling of 98 with 106 (Scheme 7) in the presence of catalyticdipalladium tris(dibenzylideneacetone)chloroform complex andtriphenylarsine (Farina. and Krishnan, J. Am. Chem. Soc., 113: 9585,1991) proceeded in high yield and gave the 9E,12Z,16E-heptadecanoate108. Exposure of 108 to tetra-n-butylammonium fluoride cleaved both the(trimethylsilyl)ethyl ester and the triethylsilyl ether but lefttert-butyldimethylsilyl ethers at C3 and C7 intact. The resulting secoacid 110 underwent facile macrolactonization to 112, and subsequentremoval of the remaining pair of TBS ethers with trifluoroacetic acidfurnished trans 9,10-dehydroepothilone D (114).

IV. EXAMPLES

The following examples are provided to illustrate certain particularfeatures of working embodiments of the present invention. The scope ofthe present invention should not be limited to those features described.

Example 1

This example describes the synthesis of compound 44 of Scheme 1. To astirred solution of the alcohol precursor to 44 (1.03 g, 5.20 mmol) inCH₂Cl₂ (20 mL) was sequentially added DHP (580 mg, 630 μL, 6.91 mmol),followed by PPTS (110 mg, 0.438 mmol). After 1.5 hours, the reaction wasquenched with solid NaHCO₃ (5 g), filtered, concentrated in vacuo andpurified by chromatography over silica gel, eluting with 30%Et₂0/petroleum ether, to give 44 (1.42 g, 5.00 mmol, 96%) as a colorlessoil: IR (neat) 2940, 1445 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 6.04 (s, 1H),4.62 (t, J=3.0 Hz, 1H), 4.26 (d, J=12.1 Hz, 1H), 4.16 (d, J=12.1 Hz,1H), 3.85-3.95 (m, 1H), 3.5-3.6 (m, 1H), 1.95 (d, J=1.5 Hz, 3H), 1.5-1.9(m, 6H); ¹³C NMR (75 MHz, CDCl₃) δ 144.6, 98.4, 75.8, 72.1, 62.5, 30.7,25.6, 22.2, 19.6; HRMS (CI) calculated for C₉H₁₆O₂ (M⁺H⁺) 283.0195,found 283.0198.

Example 2

This example describes the synthesis of compound 46. To a stirredsolution of t-BuLi (48 mL, 62.4 mmol, 1.3 M in pentane) in Et₂0 (63 mL)at −78° C. was added a solution of 44 (10.27 g, 36.4 mmol) in Et₂0 (75mL) via syringe pump over 20 minutes. After 20 minutes, the slurry wasrapidly transferred to a precooled solution of CuCN (1.58 mg, 17.7 mmol)in THF (122 mL) at −78° C. After 1 hour at −78° C. and 5 minutes at −40°C., the solution was recooled to −78° C., and a precooled solution of 42(3.40 g, 14.7 mmol) in THF (86 mL) was added via cannula. An additionalamount of THF (25 mL) was added to rinse the flask. After 30 minutes,the solution was warmed to 0° C., and after a further 10 minutes thereaction was quenched with saturated aqueous NH₄Cl (300 mL) andextracted with Et₂0 (3×150 mL). The dried (Mg₂S0₄) extract wasconcentrated in vacuo and purified by chromatography over silica gel,eluting with 15-50% Et₂0/petroleum ether, to give 46 (5.05 mg, 13.1mmol, 89%) as a colorless oil: [α]D²³ +46.1 (c 2.58, CHCl₃); IR (neat)1782, 1699 cm⁻¹; ¹H NMR (300 MHz, CDCl₃)δ 7.1-7.4 (m, 5H), 5.40 (t,J=7.1 Hz, 1H), 4.6-4.7 (m, 2H), 4.05-4.2 (m, 4H), 3.8-3.95 (m, 1H),3.45-3.6 (m, 1H), 3.28 (dd, J=3.2, 13.3 Hz, 1H), 2.9-3.05 (m, 2H), 2.76(dd, J=9.6, 13.3 Hz, 1H), 2.46 (q, J=7.3 Hz, 2H), 1.5-1.9 (m, 6H), 1.78(s, 3H); ¹³C NMR (75 MHz, CDCl₃) δ_(172.8), 153.6, 135.5, 133.8, 129.6,129.1, 127.5, 127.4, 97.8, 97.7, 66.4, 65.5, 65.4, 62.3, 55.3, 38.1,36.0, 30.8, 25.7, 22.7, 21.9, 19.7; HRMS (FAB) calculated for C₂₂H₂₈N0₅(M⁺H⁺) 386.1968, found 386.1965.

Example 3

This example describes the synthesis of compound 48. To a stirredsolution of NaHMDS (7.6 mL, 7.6 mmol, 1 M in THF) in THF (35 mL) at −78°C. was added a solution of the alcohol precursor to 46 (2.482 g, 6.41mmol) in THF (50 mL) via syringe pump over 30 minutes. An additionalamount of THF (5 mL) was added to rinse the syringe. After 20 minutes, aprecooled solution of oxaziridine (2.55 g, 9.77 mmol) in THF (8 mL) wasquickly added via cannula. After 6 minutes, the reaction was quenchedwith a solution of CSA (3.54 g, 15.2 mmol) in THF (10 mL). After 2minutes, saturated aqueous NH₄Cl (75 mL) was added. The mixture wasallowed to warm to room temperature and was concentrated in vacuo toremove THF. The aqueous layer was extracted with Et₂0 (4×100 mL). Thedried (Mg₂S0₄) extract was concentrated in vacuo and purified bychromatography over silica gel, eluting with 50-70% Et₂0/petroleumether, followed by chromatography over silica gel, eluting with 2-4%acetone/CH₂Cl₂, followed by tritration in 10% Et₂0/petroleum ether togive 48 (1.84 g, 4.5 mmol, 71%) as a white foam contaminated with asmall amount of the phenyl sulfonamide: [α]D²³ +37.2 (c 4.00, CHCl₃); IR(neat) 3476, 1781, 1699 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 7.1-7.4 (m, 5H),5.40 (m, 1H), 5.05-5.15 (m, 1H), 4.55-4.7 (m, 2H), 4.05-4.3 (m, 4H),4.02 (dd, J=3.7, 11.7 Hz, 1H), 3.8-3.95 (m, 1H), 3.79 (d, J=8.6 Hz, 1Hof a diastereomer), 3.66 (d, J=8.6 Hz, 1H of a diastereomer), 3.45-3.6(m, 1H), 3.31 (dt, J=3.0, 13.5 Hz, 1H), 2.75-2.9 (m, 1H), 2.45-2.6 (m,2H), 1.5-1.9 (m, 9H); ¹³C NMR (75 MHz, CDCl₃) δ 174.6, 174.3, 153.4,153.3, 136.2, 135.5, 135.11, 135.06, 129.6, 129.2, 127.6, 123.8, 123.1,98.1, 96.4, 70.5, 70.4, 67.1, 67.0, 65.7, 65.0, 62.4, 61.8, 55.7, 37.7,32.6, 30.7, 30.5, 25.6, 22.2, 22.1, 19.7, 19.2; HRMS (CI) calculated forC₂₂H₂₈N0₆(M+H⁺) 402.1917, found 402.1919.

Example 4

This example describes the synthesis of compound 50. To a stirredsolution of 48 (1.74 g, 4.32 mmol) in CH₂Cl₂ (22 mL) at −78° C. wasadded sequentially 2,6-lutidine (1.06 g, 1.15 mL, 9.87 mmol) followed byTBSOTf (2.07 g, 1.8 mL, 7.83 mmol). After 30 minutes, the reaction wasquenched with saturated aqueous NH₄Cl (100 mL) and extracted with Et₂0(4×100 mL). The dried (Mg₂S0₄) extract was concentrated in vacuo andpurified by chromatography over silica gel, eluting with 30-50%Et₂0/petroleum ether, to give 50 (2.06 g, 3.90 mmol, 90%) as a colorlessoil: [α]D²³ +32.3 (c 2.96, CHCl₃); IR (neat) 1782, 1714 cm⁻¹; ¹H NMR(300 MHz, CDCl₃) δ 7.15-7.4 (m, 5H), 5.35-5.5 (m, 2H), 4.55-4.7 (m, 2H),4.05-4.2 (m, 2H), 4.0-4.15 (m, 2H), 3.8-3.9 (m, 1H), 3.4-3.5 (m, 1H),3.36 (d, J=13.1 Hz, 1H), 2.7-2.8 (m, 1H), 2.71 (dt, J=1.6, 10.1 Hz, 1H),2.45-2.55 (m, 2H), 1.5-1.8 (m, 9H), 0.92 (s, 9H), 0.91 (s, 9H of adiastereomer), 0.11 (s, 3H of a diastereomer), 0.10 (s, 3H of adiastereomer), 0.08 (s, 3H of a diastereomer), 0.07 (s, 3H of adiastereomer); ¹³C NMR (75 MHz, CDCl₃) δ 173.9, 173.7, 153.3, 135.5,134.9, 129.6, 129.1, 127.5, 124.0, 97.6, 96.9, 71.1, 66.7, 65.5, 65.2,62.3, 61.9, 55.8, 37.9, 34.2, 33.7, 30.8, 30.7, 26.0, 25.7, 22.0, 21.9,19.7, 19.4, 18.5, −4.6, −4.9; HRMS (CI) calculated for C₂₈H₄₄N0₆Si (M)518.2938, found 518.2908.

Example 5

This example describes the synthesis of compound 52. To a stirredsolution of EtSH (713 mg, 850 FL, 11.5 mmol) in THF (45 mL) was added KH(106 mg, 0.93 mmol, 35% in mineral oil). After 30 minutes, the mixturewas cooled to 0° C. and a solution of 50 (2.064 g, 3.99 mmol) in THF (15mL) was added via cannula over 5 minutes. An additional amount of THF(10 mL) was added to rinse the flask. After 50 minutes at roomtemperature, the reaction was quenched with saturated aqueous NH₄Cl (50mL). Air was bubbled through the solution for 2 hours to remove excessETSH. The solution was extracted with Et₂0 (4×100 mL). The dried(Mg₂S0₄) extract was concentrated in vacuo and the residue wascrystallized by the addition of 10% Et₂O/petroleum ether to yield therecovered auxiliary (640 mg, 3.61 mmol, 93%) as a white solid. Thedecanted solution was purified by chromatography over silica gel,eluting with 10-30% Et₂0/petroleum ether, to give 52 (1.44 g, 3.50 mmol,90%) as a colorless oil: [α]D²³ −46.1 (c 3.50, CHCl₃); IR (neat) 1684cm⁻¹; ¹H NMR (300 MHz, CDCl₃) 5.35-5.5 (m, 1H), 4.55 (bs, 1H), 3.9-4.2(m, 3H), 3.8-3.9 (m, 1H), 3.45-3.6 (m, 1H), 2.75-2.9 (m, 2H), 2.4-2.6(m, 2H), 1.4-1.9 (m, 6H), 1.21 (t, J=7.5 Hz, 3H), 0.93 (s, 9H), 0.09 (s,3H), 0.06 (s, 3H of a diastereomer), 0.05 (s, 3H of a diastereomer); ¹³CNMR (75 MHz, CDCl₃) δ 205.1, 205.0, 135.24, 135.16, 97.9, 97.4, 78.6,65.7, 65.5, 62.3, 62.2, 34.5, 30.8, 25.9, 25.7, 22.6, 22.1, 22.0, 19.7,19.6, 18.4, 14.8, −4.7, −4.8; HRMS (CI) calculated for C₂0H₃₇N0₄SSi(M⁺H⁺) 401.2182, found 401.2172.

Example 6

This example describes the synthesis of compound 54. To a stirredsolution of CuI (4.85 mg, 25.5 mmol) in Et₂0 (120 mL) at 0° C. was addedMeLi (33.1 mL, 23.2 mmol, 1.4 M in Et₂0). After 15 minutes, the solutionwas cooled to −50° C. and a solution of 52 (1.78 g, 4.64 mmol) in Et₂0(90 mL) was added via cannula. An additional amount of Et₂0 (10 mL) wasadded to rinse the flask. After 30 minutes, the reaction was quenchedwith saturated aqueous NH₄Cl (300 mL) and extracted with Et₂0 (4×175mL). The dried (Mg₂S0₄) extract was concentrated in vacuo and purifiedby chromatography over silica gel, eluting with 15% Et₂0/petroleumether, to give 54 (1.36 g, 3.81 mmol, 82%) as a colorless oil: [α]D²³+14.0 (c 5.00, CHCl₃); IR (neat) 1719 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ5.35-5.5 (m, 5H), 4.5-4.55 (m, 1H), 3.9-4.1 (m, 3H), 3.75-3.9 (m, 1H),3.4-3.5 (m, 1H), 2.3-2.5 (m, 2H), 2.10 (s, 3H), 1.74 (s, 3H), 1.4-1.9(m, 6H), 0.87 (s, 9H), 0.00 (s, 6H); ¹³C NMR (75 MHz, CDCl₃), δ 211.7,135.2, 135.1, 123.8, 123.5, 97.7, 97.3, 79.0, 65.5, 65.2, 62.2, 62.1,33.2, 30.7, 25.8, 25.6, 25.5, 22.0, 19.6, 19.5, 18.2, −4.8, −4.9; HRMS(CI) calculated for C₁₉H₃₇0₄Si (M⁺H⁺) 357.2461, found 357.2455.

Example 7

This example describes the synthesis of compound 56. To a stirredsolution of the phosphonate (1.45 g, 5.82 mmol) in THF (10 mL) at −78°C. was added n-BuLi (3.6 mL, 5.76 mmol, 1.6 M in hexanes). After 15minutes, a solution of 54 (590 mg, 1.66 mmol) in THF (7 mL) was addedvia cannula. An additional amount of THF (3 mL) was added to rinse theketone flask. After 30 minutes, the mixture was allowed to warm to roomtemperature over 1 hour. After an additional 30 minutes, the reactionwas quenched with saturated aqueous NH₄Cl (50 mL) and extracted withEt₂0 (4×75 mL). The dried (Mg₂S0₄) extract was concentrated in vacuo andpurified by chromatography over silica gel, eluting with 10-20%Et₂O/petroleum ether, to give sequentially the undesired olefin isomer(40 mg, 0.089 mmol, 5%) as a colorless oil followed by the desiredproduct 54 (690 mg, 1.52 mmol, 92%) as a colorless oil: Minordiastereomer: [α]D²³ −59.2 (c 1.26, CHCl3); IR (neat) 2959, 2852, 1022cm⁻¹; ¹H NMR (300 Hz, CDCl3) δ 6.79 (s, 1H), 6.18, (s, 1H), 5.35-5.5 (m,2H), 4.55-4.65 (m, 1H), 4.05-4.15 (m, 2H), 3.8-3.9 (m, 1H), 3.45-3.6 (m,1H), 2.68 (s, 3H), 2.4-2.5 (m, 1H), 2.2-2.35 (m, 1H), 1.87 (d, J=0.9 Hz,3H), 1.76 (s, 3H), 1.4-1.9 (m, 6H), 0.84 (s, 9H), 0.07 (s, 3H), −0.10(s, 3H); ¹³C NMR (75 MHz, CDCl3) δ 164.4, 152.9, 143.5, 133.4, 126.7,126.5, 118.8, 115.2, 97.9, 97.6, 70.8, 70.5, 65.9, 62.4, 62.2, 34.5,30.9, 26.0, 25.7, 22.1, 19.8, 19.7, 19.4, 18.5, 18.4, −4.7, −4.9. Majordiastereomer: [α]D²³ +19.2 (c 3.45, CHCl₃); IR (neat) 2959, 1531, 1474cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 6.91 (s, 1H), 6.45, (s, 1H), 5.35-5.5(m, 1H), 4.5-4.6 (m, 1H), 3.9-4.2 (m, 3H), 3.8-3.9 (m, 1H), 3.45-3.6 (m,1H), 2.70 (s, 3H), 2.2-2.4 (m, 2H), 1.99 (d, J=1.0 Hz, 3H), 1.76 (s, 3H)1.4-1.9 (m, 6H), 0.88 (s, 9H), 0.04 (s, 3H), −0.01 (s, 3H); ¹³C NMR (75MHz, CDCl3) δ 164.5, 153.4, 142.5, 142.4, 133.6, 126.2, 126.1, 119.2,118.9, 115.3, 97.8, 97.5, 79.0, 78.9, 65.8, 65.6, 62.3, 62.2, 35.4,35.3, 30.1, 26.9, 26.0, 25.7, 22.0, 19.7, 19.4, 18.4, 14.1, −4.5, −4.8;HRMS (CI) calculated for C₂₄H₄₂N0₃SSi (M⁺H⁺) 452.2655, found 452.2645.

Example 8

This example describes the synthesis of the alcohol precursor tocompound 58. To a stirred solution of freshly prepared MgBr₂ (27.6 mmolof Mg, 23.8 mmol of BrCH₂CH₂Br, 50 mL of Et20) was added 56 (663 mg,1.26 mmol) in Et₂O (5 mL) at room temperature followed by saturatedaqueous NH₄Cl (approximately 50 μL). After 3.5 hours, the solution wascooled to 0° C. and carefully quenched with saturated aqueous NH₄Cl (50mL). The solution was extracted with Et₂0 (4×70 mL), and the dried(Mg₂S0₄) extract was concentrated in vacuo and purified bychromatography over silica gel, eluting with 30-50% Et₂0/petroleumether, to give the desired alcohol (459 mg, 1.26 μmol, 99%) as acolorless oil: [α]D²³ −16.8 (c 3.40, CHCl₃ ); IR (neat) 3374 cm⁻¹; ¹HNMR (300 MHz, CDCl3) δ 6.92 (s, 1H), 6.44, (s, 1H), 5.31 (t, J=7.7 Hz,1H), 4.14 (d, J=12.2 Hz, 1H), 4.1-4.2 (m, 1H), 4.00 (d, J=12.2 Hz, 1H),2.71 (s, 3H), 2.4-2.5 (m, 1H), 2.2-2.3 (m, 2H), 2.00 (s, 3H), 1.80 (s,3H), 0.89 (s, 9H), 0.06 (s, 3H), 0.04 (s, 3H); ¹³C NMR (75 MHz, CDCl3) δ164.8, 153.0, 142.4, 137.7, 124.4, 119.0, 115.4, 78.4, 62.0, 35.5, 26.0,22.2, 19.3, 18.5, 14.3, 4.5, 4.7; HRMS (CI) calculated for C₁₉H₃₄N0₂Ssi368.2080. Found 368.2061.

Example 9

This example describes the synthesis of compound 58. To a stirredsolution of the alcohol precursor (620 mg, 1.69 mmol) in CH₂Cl₂ (5.5 mL)at 0° C. was added Et₃N (360 FL, 2.58 mmol) followed by Ms₂0 (390 μL,2.24 mmol). After 10 minutes, Me₂CO (5.5 mL) was added followed by LiBr(890 mg, 10.3 mmol). After 1.8 hours at room temperature, the mixturewas concentrated in vacuo to remove the acetone, diluted with saturatedaqueous NH₄Cl (100 mL), and extracted with Et₂0 (4×200 mL). The dried(Mg₂S0₄) extract was concentrated in vacuo and purified bychromatography over silica gel, eluting with 10-20% Et₂0/petroleumether, to give 58 (607 mg, 1.44 μmol, 84%) as a colorless oil: [α]D²³+65.1 (c 2.95, CHCl₃); IR (neat) 2949, 2930, 2852, 1479, 844 cm⁻¹; ¹HNMR (300 MHz, CDCl3) δ 6.93 (s, 1H), 6.48, (s, 1H), 5.42 (1 dt, J=1.3,7.6 Hz, H), 4.16 (dd, J=5.4, 7.3 Hz, 1H), 4.06 (d, J=9.5 Hz, 1H), 3.90(d, J=9.5 Hz, 1H), 2.71 (s, 3H), 2.3-2.5 (m, 2H), 2.01 (d, J=1.1 Hz,3H), 1.83 (d, J=1.0 Hz, 3H), 0.88 (s, 9H), 0.04 (s, 3H), 0.01 (s, 3H);¹³C NMR (75 MHz, CDCl3) δ 164.6, 153.2, 142.1, 133.3, 128.2, 119.2,115.4, 78.1, 35.7, 32.6, 26.0, 22.2, 19.4, 18.4, 13.1, −4.5, −4.8; HRMS(CI) calculated for C1₉H₃₃N0₂SSi₈₁Br (M⁺H⁺) 430.1235, found 430.1244.

Example 10

This example describes the synthesis of compound 60. To a stirredsolution of Ph₃PMeBr (1.53 g, 4.28 mmol) in THF (16.2 mL) at −78° C. wasadded n-BuLi (2.7 mL, 4.32 mmol, 1.6 M in hexanes) over a period of 3minutes. After 35 minutes, a pre-cooled solution of 58 (607 mg, 1.41mmol) in THF (7 mL) was added dropwise to the ylide over a period of 5minutes. An additional portion of THF (6 mL) was added to rinse theflask. After 15 minutes, the mixture was allowed to warm to −20° C.After an additional 20 minutes, the reaction was quenched with MeOH, andwas concentrated in vacuo. The residue was purified by chromatographyover silica gel, eluting with 0-6% MeOH/CH₂Cl₂, followed by dilutionwith CH₂Cl₂ and an H₂O wash to remove excess Ph₃MeBr, to give 60 (890mg, 1.26 mmol, 89%) a an off-white foam: [α]D²³ +6.4 (c 1.06, CHCl3); IR(neat) 2959, 2930, 2853, 1440; ¹H NMR (300 MHz, CDCl₃) δ 7.6-7.9 (1 m,5H), 6.89 (s, 1H), 6.33, (s, 1H), 5.20 (m, 1H), 3.95 (m, 1H), 3.5-3.8(m, 2H), 2.65 (s, 3H), 2.1-2.3 (m, 2H), 1.88 (s, 3H), 1.83 (s, 3H), 0.78(s, 9H), −0.07 (s, 3H), −0.09 (s, 3H); ¹³C NMR (75 MHz, CDCl₃) δ 164.7,153.0, 142.1, 135.6, 133.9, 130.9, 130.7, 124.7, 118.8, 117.5, 115.6,78.2, 35.9, 26.0, 24.7, 23.7, 22.6, 21.9, 19.4, 18.3, 14.4, −4.6, −4.8;HRMS (CI) calculated for C₃₈H₄₉NOPSSi (M⁺H⁺) 626.3042, found 626.3028.

Example 11

This example describes the synthesis of compound 66. To a stirredsolution of i-Pr₂NH (390 μL, 2.78 mmol) in THF (0.7 mL) was added n-BuLi(1.73 mL, 2.77 mmol, 1.6 M in hexanes) dropwise at −78° C. After 5minutes, the solution was warmed to 0° C. for 45 minutes and recooled to−78° C. To the stirring solution of LDA was added a precooled solutionof 62 (718 mg, 2.53 mmol) in TBF (0.6 mL) dropwise via cannula over 5minutes. An additional amount of THF (0.4 mL) was used to rinse theflask. After an additional 50 minutes at −78° C., a precooled solutionof 64 (484 mg, 2.33 mmol) in THF (0.6 mL) was added dropwise viacannula. An additional amount of THF (0.4 mL) was used to rinse theflask. After 30 minutes, the reaction was quenched with saturatedaqueous NH₄Cl (20 mL) and extracted with Et₂0 (4×25 mL). The dried(Mg₂S0₄) extract was concentrated in vacuo and purified bychromatography over silica gel, eluting with 6-10% Et₂0/petroleum ether,to give 66 (694 mg, 1.41 mmol, 61%) as a colorless oil: [α]D²³ −25.1 (c3.05, CHCl3); IR (neat) 3483, 1695 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 7.25(d, J=8.7 Hz, 2H), 6.86 (d, J=8.7 Hz, 2H), 5.65-5.85 (m, 1H), 4.9-5.1(m, 2H), 4.44 (s, 2H), 3.93 (dd, J=4.5, 6.4 Hz, 1H), 3.80 (s, 3H),3.55-3.65 (m, 3H), 3.46 (dd, J=6.1, 8.9 Hz, 1H), 3.15-3.25 (m, 1H),2.05-2.2 (m, 2H), 1.8-1.9 (m, 1H), 1.18 (s, 3H), 1.11 (s, 3H), 1.05 (d,J=6.8 Hz, 3H), 0.94 (d, J=7.9 Hz, 3H), 0.89 (s, 9H), 0.07 (s, 3H), 0.06(s, 3H); ¹³C NMR (75 MHz, CDCl₃) δ 221.7, 159.3, 136.5, 130.9, 129.4,116.9, 113.9, 73.2, 73.1, 72.9, 55.4, 54.4, 41.9, 39.8, 36.4, 29.9,26.3, 23.9, 19.3, 18.4, 14.3, 10.2, −3.3, −3.8; HRMS (CI) calculated forC₂₈H₄₉0₅Si (M⁺H⁺) 493.3349, found 493.3350.

Example 12

This example describes the synthesis of compound 68. To a stirredsolution of 66 (61 mg, 0.124 mmol) in CH₂Cl₂ (0.7 mL) at 0° C. wassequentially added Et₃N (29 mg, 40 μL, 0.287 mmol) followed by TBSOTf(43.7 mg, 38 μL, 0.165 mmol) at 0° C. After 45 minutes, the reaction wasquenched with saturated aqueous NH₄Cl (20 mL) and extracted with Et₂0(4×25 mL). The dried (Mg₂S0₄) extract was concentrated in vacuo andpurified by chromatography over silica gel, eluting with 3-10%Et₂0/petroleum ether, to give 68 (66.5 mg, 0.111 mmol, 89%) as acolorless oil: [α]D²³ −16.0 (c 2.92, CHCl₃); IR (neat) 1695 cm⁻¹; ¹H NMR(300 MHz, CDCl₃) δ 7.23 (d, J=8.6 Hz, 2 h), 6.86 (d, J=8.6 Hz, 2 h),5.7-5.9 (m, 1H), 4.99 (d, J=6.4 Hz, 1H), 4.95 (s, 1H), 4.40 (s, 2H),3.9-4.0 (m, 1H), 3.85 (d, J=7.3 Hz, 1H), 3.80 (s, 3), 3.58 dd, J=5.7,9.2 Hz, 1H), 3.27 (qn, J=7.4 Hz, 1H), 3.19 (t, J=7.4 Hz, 1H) 2.0-2.2 (m,2H), 1.8-1.9 (m, 1H), 1.13 (s, 3H), 1.04 (s, 3H), 1.02 (3H, d, J=7.0Hz), 0.96 (3H, d, J=6.9 Hz), 0.891 (s, 9H), 0.887 (s, 9H), 0.06 (s, 6H),0.05 (s, 3H), 0.03 (s, 3H); ¹³C NMR (75 MHz, CDCl₃) δ 219.2, 159.3,137.1, 131.0, 129.5, 116.5, 113.9, 76.5, 73.1, 71.8, 55.5, 54.2, 46.2,39.8, 38.9, 26.5, 26.3, 25.3, 18.7, 18.4, 18.0, 17.0, 16.6, −3.0, −3.3,−3.5, −3.8; HRMS (CI) calculated for C₃₄H₆₃0₅Si₂ (M⁺H⁺) 607.4214, found607.4212.

Example 13

This example describes the synthesis of compound 70. To a stirredsolution of 68 (722 mg, 1.19 mmol) in THF (9 mL) and H₂O (8.5 mL) wassequentially added OsO₄ (400 μL, 4% in H₂O) followed by NaIO₄ (1.065 g,4.98 mmol). After 18 hours, the reaction was quenched with saturatedaqueous Na₂S₂O₃ (50 mL). After 30 minutes, saturated aqueous NaCl (100mL) was added and the mixture was extracted with Et₂O (4×100 mL). Thedried (Mg₂SO₄) extract was concentrated in vacuo to give the aldehyde asa colorless oil: [α]D²³ −13.0 (c 4.20, CHCl₃); IR (neat) 1725, 1689cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 9.74 (1 t, J=1.2 Hz, 1H), 7.22 (d, J=8.5Hz, 2 h), 6.85 (d, J=8.5 Hz, 2H), 4.46 (t, J=5.3 Hz, 1H), 4.39 (s, 2H),3.82 (d, J=7.9 Hz, 1H), 3.80 (s, 3H), 3.58 (dd, J=6.0, 9.1 Hz, 1H), 3.27(qn, J=7.4 Hz, 1H), 3.19 (dd, J=6.9, 8.9 Hz, 1H) 2.3-2.5 (m, 2H),1.6-1.8 (m, 1H), 1.14 (s, 3H), 1.06 (s, 3H), 1.00 (d, J=7.0 Hz, 3H),0.94 (d, J=7.0 Hz, 3H), 0.88 (s, 9H), 0.87 (s, 9H), 0.08 (s, 3H), 0.05(s, 6H), 0.03 (s, 3H); ¹³C NMR (75 MHz, CDCl₃) δ 219.0, 201.5 159.3,130.9, 129.5, 113.9, 76.8, 73.1, 71.7, 71.6, 55.4, 53.7, 49.7, 46.2,38.8, 26.4, 26.1, 24.4, 18.7, 18.3, 17.0, 15.7, −3.4, −3.5, −3.9, −4.3;HRMS (CI) calculated for C₃₃H₆₁O₆Si₂ (M⁺H⁺) 609.4007, found 607.4005.

To a stirred solution of the crude aldehyde (1.19 mmol) prepared abovein t-BuOH (16 mL) and H₂O (15 mL) was sequentially added2-methyl-2-butene (3 mL) followed by NaH₂PO₄ (1.06 g, 11.6 mmol) andNaClO₂ (490 mg, 5.4 mmol). After 1 hour, the reaction was quenched withsaturated aqueous NaCl (75 mL) and extracted with Et₂O (4×100 mL). Thedried (Mg₂SO₄) extract was concentrated in vacuo to give crude 70 as acolorless oil: [α]D²³ −26.8 (c 4.20, CHCl₃); IR (neat) 2400-3400, 1722cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 7.23 (d, J=8.6 Hz, 2H), 6.85 (d, J=8.6Hz, 2H), 4.40 (s, 2H), 4.3-4.4 (m, 1H), 3.82 (d, J=7.9 Hz, 1H), 3.80 (s,3H), 3.58 (dd, J=5.8, 9.1 Hz, 1H), 3.32 (qn, J=7.2 Hz, 1H), 3.18 (dd,J=7.2, 8.9 Hz, 1H) 2.46 (dd, J=2.9, 16.4 Hz, 1H), 2.28 (dd, J=6.8, 16.4Hz, 1H), 1.7-1.85 (m, 1H), 1.15 (s, 3H), 1.07 (s, 3H), 1.02 (d, J=6.9Hz, 3H), 0.95 (d, J=7.0 Hz, 3H), 0.88 (s, 9H), 0.87 (s, 9H), 0.08 (s,3H), 0.05 (s, 6H), 0.04 (s, 3H); ¹³C NMR (75 MHz, CDCl₃) δ 218.7, 178.0,159.3, 130.9, 129.5, 113.9, 73.8, 73.1, 71.7, 55.5, 53.7, 46.3, 40.4,38.9, 26.4, 26.4, 26.2, 24.0, 18.7, 18.4, 17.0, 15.8, −3.3, −3.5, −4.1,−4.4; HRMS (CI) calculated for C₃₃H₆₁O₇Si₂ 625.3966. Found 625.3957.

Example 14

This example describes the synthesis of compound 72. To a stirredsolution of crude 70 (1.19 mmol) in PhH (20 mL) and MeOH (2.5 mL) wasadded TMSCHN₂ (700 μL, 1.4 mmol, 2 M in hexanes). After 45 minutes, themixture was concentrated in vacuo and purified by chromatography oversilica gel, eluting with 5-10% Et₂O/petroleum ether, to give 72 (502 mg,0.797 mmol, 66% over three steps) as a colorless oil: [α]D²³ −27.1 (c1.03, CHCl₃); IR (neat) 1741, 1690 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 7.23(d, J=8.5 Hz, 2H), 6.86 (d, J=8.5 Hz, 2H), 4.39 (s, 2H), 4.3-4.4 (m,1H), 3.83 (d, J=7.8 Hz, 1H), 3.80 (s, 3H), 3.66 (s, 3H), 3.58 (dd,J=5.7, 9.1 Hz, 1H), 3.31 (qn, J=7.2 Hz, 1H), 3.18 (dd, J=7.3, 9.1 Hz,1H), 2.46 (dd, J=3.1, 16.1 Hz, 1H), 2.26 (dd, J=7.0, 16.1 Hz, 1H),1.7-1.85 (m, 1H), 1.14 (s, 3H), 1.06 (s, 3H), 1.01 (d, J=6.9 Hz, 3H),0.95 (d, J=6.9 Hz, 3H), 0.88 (s, 9H), 0.87 (s, 9H), 0.08 (s, 3H), 0.05(s, 6H), 0.02 (s, 3H); ¹³C NMR (75 MHz, CDCl₃) δ 218.5, 172.7, 159.3,131.0, 129.5, 113.9, 74.1, 73.1, 71.8, 55.5, 53.6, 51.8, 46.3, 40.4,38.9, 26.5, 26.2, 24.0, 18.8, 18.7, 18.4, 17.0, 15.7, −3.3, −3.5, −4.3,−4.4; HRMS (CI) calculated for C₃₃H₆₃O₇Si₂ (M⁺H⁺) 639.4112, found639.4112.

Example 15

This example describes the synthesis of compound 74. To a stirredsolution of 72 (290 mg, 0.455 mmol) in EtOH (7 mL) was added palladiumon carbon (101 mg, 10% Pd) and the mixture was placed under anatmosphere of H₂. After 0.75 hour, the H₂ atmosphere was replaced by Arand the reaction was filtered through Celite (EtOH rinse). The liquidwas concentrated in vacuo and the residue was purified by chromatographyover silica gel, eluting with 10-30% Et₂O/petroleum ether, to give 74(216 mg, 0.418 mmol, 92%) as a colorless oil: [α]D²³ −13.2 (c 1.07,CHCl₃); IR (neat) 3538, 1743, 1694 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 4.40(dd, J=2.9, 6.9 Hz, 1H), 3.93 (dd, J=2.0, 7.8 Hz, 1H), 3.67 (s, 3H),3.6-3.7 (m, 1H), 3.5-3.6 (m, 1H), 3.31 (qn, J=7.5 Hz, 1H), 2.43 (dd,J=2.7, 16.3 Hz, 1H), 2.26 (dd, J=6.9, 16.3 Hz, 1H), 1.55-1.65 (m, 1H),1.22 (s, 3H), 1.13 (s, 3H), 1.09 (d, J=7.0 Hz, 3H), 0.95 (d, J=7.1 Hz,3H), 0.92 (s, 9H), 0.87 (s, 9H), 0.12 (s, 3H), 0.10 (s, 3H), 0.09 (s,3H), 0.01 (s, 3H), ¹³C NMR (75 MHz, CDCl₃) δ 218.4, 172.8, 78.2, 73.6,64.9, 53.9, 51.9, 47.0, 40.3, 39.8, 29.9, 26.4, 26.2, 24.1, 19.1, 18.6,18.4, 16.1, −3.4, −3.6, −4.3, −4.4; HRMS (CI) calculated for C₂₆H₅₃Si₂O₆(M⁺H⁺) 517.3381, found 517.3361.

Example 16

This example describes the synthesis of compound 76. To a stirredsolution of 74 (700 mg, 1.36 mmol) and powdered molecular sieves (1.5 g)in CH₂Cl₂ (35 mL) was sequentially added NMO (420 mg, 3.56 mmol)followed by TPAP (137.5 mg, 106 mmol). After 1 hour, the mixture wasdiluted with 30% Et₂O/petroleum ether (100 mL) and filtered throughsilica gel (30% Et₂O/petroleum ether rinse). The filtrate wasconcentrated in vacuo to give 76 (698 mg, 1.36 mmol, 99%) as a colorlessoil: [α]D²³ −32.1 (c 1.76, CHCl₃); IR (neat) 1746, 1690 cm⁻¹; ¹H NMR(300 MHz, CDCl₃) δ 9.73 (d, J=2.1 Hz, 1H), 4.41 (dd, J=3.2, 6.9 Hz, 1H),4.08 (dd, J=2.1, 8.3 Hz, 1H), 3.67 (s, 3H), 3.25 (qn, J=7.0 Hz, 1H),2.41 (1Hdd, J=3.3, 16.1 Hz, 1H), 2.2-2.35 (m, 2H), 1.24 (s, 3H), 1.12(d, J=7.1 Hz, 3H), 1.10 (d, J=6.9 Hz, 3H), 1.09 (s, 3H), 0.89 (s, 9H),0.87 (s, 9H), 0.11 (s, 3H), 0.090 (s, 3H), 0.085 (s, 3H), 0.01 (s, 3H);¹³C NMR (75 MHz, CDCl₃) δ 218.0, 204.4, 172.6, 76.5, 73.9, 53.8, 51.9,51.0, 46.8, 40.4, 29.9, 26.4, 24.0, 19.2, 18.6, 18.4, 15.9, 12.7, −3.4,−3.6, −4.3, −4.4; HRMS (CI) calculated for C₂₆H₅₁Si₂O₆ (M⁺H⁺) 515.3225,found 515.3218.

Example 17

This example describes the synthesis of compound 78. To LHMDS [HMDS (280μL, 1.31 mmol) in THF (650 μL) at −78° C. was added n-BuLi (820 μL, 1.31mmol, 1.6 M in hexanes). After 5 minutes, the solution was warmed to 0°C. and added dropwise to a stirred solution of the salt 58 (930 mg, 1.32mmol) in THF (17 mL) at −78° C. via cannula. After 15 minutes, thesolution was warmed to −30° C. After an additional 15 minutes, thesolution was re-cooled to −78° C. and added dropwise to a pre-cooledsolution of the 76 (520 mg, 1.03 mmol) in THF (0.6 mL) via cannula. Themixture was then allowed to warm slowly to room temperature over aperiod of 1 hour. After 10 minutes at room temperature, the reaction wasquenched with saturated aqueous NH₄Cl (25 mL) and was concentrated invacuo to remove THF. The solution was extracted with Et₂O (4×50 mL), andthe dried (Mg₂SO₄) extract was concentrated in vacuo and purified bychromatography over silica gel, eluting with 2-10% Et₂O/petroleum ether,to give 78 (728 mg, 0.84 mmol, 82%) as a colorless oil: [α]D²³ +3.6 (c1.00, CHCl₃); IR (neat) 1743, 1699 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 6.91(s, 1H), 6.45 (s, 1H), 5.58 (t, J=9.2 Hz, 1H), 5.2-5.35 (m, 1H), 5.16(t, J=6.6 Hz, 1H), 4.39 (1H, dd, J=3.1, 6.9 Hz), 4.09 (1H, t, J=6.6 Hz),3.8-3.9 (m, 1H), 3.6-3.7 (m, 1H); 3.66 (s, 3H), 3.03 (qn, J=6.7 Hz, 1H),2.70 (s, 3H), 2.65-2.75 (m, 2H), 2.3-2.5 (m, 2H), 2.15-2.35 (m, 3H),1.99 (s, 3H), 1.64 (s, 3H), 1.19 (s, 3H), 1.06 (s, 3H), 1.03 (d, J=7.1Hz, 3H), 1.00 (d, J=7.0 Hz, 3H), 0.92 (s, 9H), 0.88 (s, 9H), 0.86 (s,9H), 0.08 (s, 3H), 0.07 (s, 6H), 0.04 (s, 3H), 0.00 (s, 3H), −0.01 (s,3H); ¹³C NMR (75 MHz, CDCl₃) δ 218.0, 172.6, 164.5, 153.4, 142.5, 135.5,131.7, 128.7, 122.2, 119.0, 115.2, 79.1, 76.1, 74.2, 53.5, 51.8, 46.4,40.4, 37.9, 35.6, 30.9, 26.4, 26.2, 26.0, 24.0, 23.9, 19.4, 19.3, 18.7,18.4, 14.9, 14.1, −3.3, −3.7, −4.3, −4.4, −4.7; HRMS (CI) calculated forC₄₆H₈₆O₆Si₃SN (M⁺H⁺) 864.5484, found 864.5510.

Example 18

This example describes the synthesis of compound 80. To a stirredsolution of 78 (51 mg, 59 μmol) in i-PrOH (1 mL) was added NaOH (11.5FL, 62 μmol, 5.4 M in H₂O), and the mixture was heated at 45° C. in asealed tube. After 16 hours, the solution was concentrated, diluted withaqueous HCl (20 mL, 0.5 M) and extracted with Et₂O (4×50 mL). The dried(Mg₂SO₄) extract was concentrated in vacuo and purified bychromatography over silica gel, eluting with 5-20% EtOAc/hexanes, togive 80 (33 mg, 34 Fmol, 66%) as a colorless oil: IR (neat) 3500-2500,1713 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 6.93 (s, 1H), 6.67 (s, 1H), 5.52(t, J=9.6 Hz, 1H), 5.3-5.4 (m, 1H), 5.23 (t, J=7.4 Hz, 1H), 4.41 (dd,J=3.3, 6.6 Hz, 1H), 3.75-3.85 (m, 1H), 2.9-3.1 (m, 2H), 2.71 (s, 3H),2.5-2.8 (m, 2H), 2.1-2.6 (m, 4H), 1.9-2.1 (m, 1H), 1.93 (s, 3H), 1.71(s, 3H), 1.16 (s, 3H), 1.13 (s, 3H), 1.04 (d, J=7.0 Hz, 3H), 9.94(obscured d, 3H), 0.92 (s, 9H), 0.88 (18H, s), 0.12 (s, 6H), 0.09 (s,3H), 0.06 (s, 3H), 0.03 (s, 3H), −0.01 (s, 3H); HRMS (CI) calculated forC₄₅H₈₄O₆Si₃SN (M⁺H⁺) 850.5327, found 850.5281.

Example 19

This example describes the synthesis of compound 82. To a stirredsolution of 80 (154 mg, 181 μmol) in THF (3.9 mL) at 0° C. was addedTBAF (1.1 mL, 1.1 mmol, 1 M in THF). The solution was allowed to warmslowly to room temperature overnight. After 16 hours, the mixture wasdiluted with EtOAc, washed with saturated aqueous NH₄Cl (50 mL), andextracted with EtOAc (4×100 mL). The dried (Mg₂SO₄) extract wasconcentrated in vacuo and purified by chromatography over silica gel,eluting with 2-5% MeOH/CH₂Cl₂, to give 82 (118.5 mg, 160 μmol, 89%) as awhite foam: [α]D²³ −2.6 (c 3.50, CHCl₃); IR (neat) 3500-2500, 1709 cm⁻¹;¹H NMR (300 MHz, CDCl₃) δ 6.95 (s, 1H), 6.70 (s, 1H), 5.56 (t, J=10.0Hz, 1H), 5.3-5.45 (m, 1H), 5.24 (t, J=7.3 Hz, 1H), 4.35-4.45 (m, 1H),4.16 (t, J=6.2 Hz, 1H), 3.75-3.85 (m, 1H), 3.03 (m, 2H), 2.75-2.85 (m,1H), 2.72 (s, 3H), 2.65-2.75 (m, 1H), 2.2-2.7 (m, 5H), 1.99 (s, 3H),1.74 (s, 3H), 1.15 (s, 3H), 1.14 (s, 3H), 1.04 (d, J=7.1 Hz, 3H), 0.98(d, J=6.9 Hz, 3H), 0.92 (s, 9H), 0.87 (s, 9H), 0.12 (s, 3H), 0.10 (s,3H), 0.07 (s, 3H), 0.06 (s, 3H); ¹³C NMR (75 MHz, CDCl₃) δ 218.1, 176.0,165.1, 152.4, 141.9, 137.5, 131.6, 127.8, 120.8, 118.8, 115.1, 77.2,76.0, 73.5, 53.6, 46.3, 40.1, 38.0, 34.1, 30.8, 26.2, 26.0, 23.7, 23.5,19.0, 18.9, 18.7, 18.5, 18.1, 15.0, 14.6, −3.6, −4.1, −4.2, −4.6; HRMS(CI) calculated for C₃₉H₇₀O₆Si₂SN (M⁺H⁺) 736.4462, found 736.4451.

Example 20

This example describes the synthesis of the protected alcohol precursorto compound 84. To a stirred solution of 82 (57.2 mg, 78.0 μmol) in THF(1.3 mL) at 0° C. was added Et₃N (19 FL, 136 μmol) followed by2,4,6-trichlorobenzoyl chloride (14 μL, 89.5 mmol). After 45 minutes,the mixture was diluted with THF (1 mL) and PhMe (1.7 mL) and was addedvia syringe pump to a stirring solution of DMAP (16.3 mg, 133 μmol) inPhMe (18 mL) at 75° C. over a period of 3.5 hours. After an additional 1hour, the solution was cooled, diluted with EtOAc, washed with saturatedaqueous NH₄Cl (50 mL), and extracted with EtOAc (4×100 mL). The dried(Mg₂SO₄) extract was concentrated in vacuo and purified bychromatography over silica gel, eluting with 2-10% EtOAc/hexanes, togive the protected alcohol precursor to compound 84 (35.5 mg, 49.5 μmol,63%) as a colorless oil contaminated with a small amount of an oligomer:IR (neat) 1738, 1709 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 6.95 (s, 1H), 6.50(s, 1H), 5.65 (t, J=10.0 Hz, 1H), 5.3-5.45 (m, 2H), 5.11 (t, J=6.3 Hz,1H), 4.45 (dd, J=2.8, 8.0 Hz, 1H), 3.7-3.8 (m, 1H), 3.19 (dd, J=9.5,15.7 Hz, 1H), 3.0-3.1 (m, 1H), 2.71 (s, 3H), 2.2-2.7 (m, 6H), 2.09 (s,3H), 1.74 (s, 3H), 1.13 (s, 3H), 1.11 (s, 3H), 1.07 (d, J=7.1 Hz, 3H),0.99 (d, J=7.0 Hz, 3H), 0.93 (s, 9H), 0.87 (s, 9H), 0.14 (s, 3H), 0.11(s, 3H), 0.07 (s, 3H), 0.06 (s, 3H); ¹³C NMR (75 MHz, CDCl₃) δ 216.0,169.9, 164.9, 152.9, 137.8, 136.5, 130.8, 126.9, 121.1, 118.9, 116.6,106.3, 78.1, 76.4, 73.1, 54.0, 47.4, 41.2, 39.0, 31.0, 26.4, 26.3, 26.1,24.5, 21.3, 20.5, 19.7, 19.5, 18.9, 18.3, 15.2, 14.7, −3.4, −3.5, −4.6;HRMS (CI) calculated for C₃₉H₆₈O₅Si₂SN (M⁺H⁺) 718.4357, found 718.4354.

Example 21

This example describes the synthesis of compound 84. To a stirredsolution of the protected alcohol precursor to compound 82 (16.5 mg, 23mmol) in CH₂Cl₂ (110 μL) at 0° C. was added TFA (100 μL). After 4.5hours, the mixture was concentrated in vacuo and purified bychromatography over silica gel, eluting with 20-50% EtOAc/hexanes, togive 84 (9.3 mg, 19 Fmol, 83%) as a colorless oil: [α]D²³ −133.0 (c1.30, CHCl₃); IR (neat) 3438, 1738, 1694 cm⁻¹; ¹H NMR (400 MHz, CDCl₃) δ6.97 (s, 1H), 6.52 (s, 1H), 5.5-5.7 (m, 2H), 5.35-5.45 (m, 1H), 5.15 (t,J=7.1 Hz, 1H), 4.22 (dd, J=2.5, 9.4 Hz, 1H), 3.7-3.8 (m, 1), 3.1-3.2 (m,1H), 3.04 (dd, J=7.7, 15.3 Hz, 1H), 2.85-2.95 (m, 1H), 2.70 (s, 3H),2.4-2.7 (m, 6H), 2.06 (s, 3H), 1.72 (s, 3H), 1.27 (s, 3H), 1.1-1.2(obscured d, 3H×2), 1.12 (s, 3H); ¹³C NMR (100.5 MHz, CDCl₃) δ 220.4,170.7, 152.2, 138.1, 137.0, 132.3, 128.1, 119.0, 118.9, 115.7, 77.4,74.1, 73.0, 52.7, 44.2, 39.1, 36.9, 31.4, 30.2, 29.7, 23.9, 21.8, 20.4,19.0, 17.5, 16.0, 13.3; HRMS (CI) calculated for C₂₇H₄₀O₅SN (M⁺H⁺)490.2627, found 490.2627.

Example 22

This example describes the synthesis of 86. To a stirred solution of 84(6.6 mg, 13.5 μmol) in CH₂Cl₂ (2 mL) at reflux was added portionwise alarge excess of KO₂CN═NCO₂K followed by AcOH (2 equivalents) until thereaction was complete by TLC (25 hours). The KOAc precipitate wasperiodically removed during the course of the reaction. The solution wasfiltered through SiO₂ (Et₂O rinse), concentrated in vacuo, and purifiedby chromatography over silica gel, eluting with EtOAc/hexanes/CH₂Cl₂(1:4:5-1:1:2), to give 86 (3.4 mg, 6.9 μmol, 52%) as a colorless oil:[α]D²³ −86.7 (c 0.15, CHCl₃); ¹H NMR (400 MHz, CDCl₃) δ 6.95 (s, 1H),6.58 (s, 1H), 5.22 (d, J=8.8 Hz, 1H), 5.1-5.2 (m, 1H), 4.30 (d, J=11.2Hz, 1H), 3.7-3.8 (m, 1H), 3.4-3.55 (m, 1H), 3.15 (q, J=4.8 Hz, 1H),3.0-3.1 (m, 1H), 2.69 (s, 3H), 2.5-2.7 (m, 1H), 2.05-2.5 (m, 4H), 2.06(s, 3H), 1.8-1.9 (m, 1H), 1.7-1.8 (m, 1H), 1.34 (s, 3H), 1.2-1.3 (m,4H), 1.19 (d, J=7.0 Hz, 3H), 1.07 (s, 3H), 1.01 (d, J=6.9, 3H); ¹³C NMR(100.5 MHz, CDCl₃) δ 220.8, 170.6, 165.2, 152.3, 139.4, 138.7, 121.1,119.5, 115.9, 79.2, 74.4, 72.6, 53.7, 42.0, 39.9, 32.8, 32.0, 31.9,25.6, 23.1, 19.3, 18.3, 16.1, 16.0, 13.6.

Example 23

This example describes the synthesis of compound 4. To a stirredsolution of 86 (1.5 mg, 3.05 mmol) in CH₂Cl₂ (400 mL) at −50° C. wasadded a solution of dimethyl dioxirane until all of the startingmaterial had been consumed as judged by TLC. The solution wasconcentrated in vacuo and purified by chromatography over silica gel,eluting with 50-60% EtOAc/pentane, to give epothilone B (4) (1.2 mg, 2.4μmol, 78%) as a colorless oil: [α]D²³ −36.7 (c 0.12, CHCl₃); ¹H NMR (400MHz, CDCl₃) δ 6.97 (s, 1H), 6.59 (s, 1H), 5.42 (dd, J=2.8, 7.9 Hz, 1H),4.1-4.3 (m, 2H), 3.77 (bs, 1H), 3.2-3.35 (m, 1H), 2.81 (dd, J=4.5, 7.6Hz, 1H), 2.69 (s, 3H), 2.66 (bs, 1H), 2.4-2.55 (m, 1H), 2.36 (dd, J=2.3,13.6 Hz, 1H), 2.1-2.2 (m, 1H), 2.09 (s, 3H), 1.85-2.0 (m, 1H), 1.6-1.7(m, 1H), 1.35-1.55 (m, 4H), 1.37 (s, 3H), 1.28 (s, 3H), 1.17 (d, J=6.8Hz, 3H), 1.08 (s, 3H), 1.00 (d, J=7.1 Hz); ¹³C NMR (100.5 MHz, CDCl₃) δ220.6, 170.5, 165.1, 151.8, 137.5, 119.7, 116.1, 74.1, 72.9, 61.6, 61.3,53.1, 42.9, 39.2, 36.4, 32.3, 32.1, 30.8, 29.7, 22.7, 22.3, 21.4, 19.6,19.1, 17.0, 15.8, 13.6; HRMS (CI) calculated for C₂₇H₄₂NO₅S (M+H⁺)492.2784, found 492.2775.

Example 24

This example describes the synthesis of alkyne 88 as illustrated inScheme 4. To a stirred solution of potassium tert-butoxide (0.27 mL, 1.0M THF solution) in THF (0.5 mL) at −78° C. was added a solution of(diazomethyl)phosphonate (40.2 mg, 1.25 mmol) in THF (0.5 mL). After 5minutes a solution of 76 (110 mg, 0.21 mmol) in THF (0.5 mL) was addeddropwise, and the mixture was stirred at −78° C. for 12 hours. Themixture was then warmed to room temperature and was quenched withsaturated aqueous NH₄Cl. The aqueous layer was extracted with 3×5 mLportions of Et₂O, and the combined organic extracts were dried (MgSO₄),concentrated in vacuo, and purified by chromatography (SiO₂, 5%Et₂O/hexane) to give 88 (85 mg, 80%) as colorless crystals: [α]D²⁴ −24.1(c 1.12, CHCl₃); mp 52-54° C.; IR (film) 3310 2951, 2927, 2883, 2854,1743, 1691, 1472, 1254, 1089, 990, 837, 775 cm⁻¹; ¹H NMR (CDCl₃, 300MHz) δ 4.45 (1H, dd, J=3.1, 7.5 Hz), 3.76 (1H dd, J=2.1, 6.4 Hz), 3.65(1H, s), 3.33 (1H, qn, J=7.5) 2.40-2.26 (3H, m), 2.06 (1H, s), 1.24 (3H,s), 1.18 (3H, d J=6.9 Hz), 1.17 (3H, 3H), 1.07 (3H, d, J=7.0 Hz), 0.92(9H, s), 0.86 (9H, s), 0.08 (3H, s), 0.07 (3H, s), 0.00 (3H, s); ¹³C NMR(CDCl₃, 75 MHz) δ 218.6, 172.3, 85.6, 75.7, 73.3, 70.8, 53.9, 46.5,32.1, 26.1, 23.7, 18.7, 18.5, 18.2, 15.8, −3.3, −3.9, −4.5, −4.7; HRMS(CI) calculated for C₂₇H₅₂Si₂O₅ (M+H⁺) 512.3353, found 512.3342.

Example 25

This example describes the synthesis of enyne 90 as illustrated inScheme 4. To a stirred solution of 88 (70.0 mg, 0.135 mmol) in Et₂O (1.0mL) and DMF (0.4 mL) at room temperature was added Et₃N (18.8 μL, 0.135mmol) and CuI (25.7 mg, 0.135 mmol). After the mixture turned clear(approximately 5 minutes), a solution of 56 (29.1 mg, 0.068 mmol) inEt₂O (1.0 mL) was added, and the mixture was stirred for 18 hours. Thereaction mixture was quenched with saturated aqueous Na₂S₂O₃ (5 mL) andwas extracted with Et₂O (3×2 mL). The combined organic extracts weredried (MgSO₄), concentrated in vacuo, and purified by flashchromatography over silica gel (50-60% CH₂Cl₂/hexanes) to give 90 (35.6mg, 60%) as a colorless oil: [α]D²³ −16.7 (c 1.01); IR (film) 2927,2857, 2371, 2341, 1743, 1683, 1648, 1482, 1251, 991, 837 cm⁻¹; ¹H NMR(CDCl₃, 300 MHz) δ 6.91(1H, s), 6.46 (1H, s), 5.36 (1H, t, J=4.7 Hz),4.45 (1H, dd, J=3.1, 6.9), 4.11 (1H, t, J=6.6), 3.76-3.72 (1H, m),3.74-3.67 (1H, m), 3.67 (3H, s), 3.36-3.31 (1H, qn, J=6.8), 2.71 (3H,s), 2.41-2.25 (7H, m), 2.01 (3H, s), 1.80 (3H, s), 1.24 (3H, s), 1.16(3H, s), 1.12 (3H, d, J=7.0), 1.05 (3H, d, J=6.8), 0.92 (9H, s), 0.88(9H, s), 0.87 (9H, s), 0.09 (3H, s), 0.06 (6H, s), 0.04 (3H, s), 0.01(3H, s); −0.00 (3H, s); ¹³C NMR (CDCl₃, 75 MHz): δ 218.0, 172.4, 164.3,153.2, 142.5, 132.2, 122.2, 118.6, 118.9, 83.1, 80.2, 78.6, 75.9, 73.5,53.7, 51.6, 46.3, 40.4, 35.7, 32.6, 29.7, 29.2, 26.1, 26.0, 25.8, 23.8,21.7, 19.2, 18.9, 18.4, 18.2, 16.2, 15.7, 13.9, −3.3, −3.9, −4.4, −4.6,−4.7, −4.9; HRMS (CI) calculated for C₄₆H₃₄O₆Si₃ SN (M+H⁺) 862.5327,found 862.5325.

Example 26

This example describes the synthesis of methyl ester 80 from compound 90as illustrated in Scheme 4. A suspension of 90 (10 mg, 0.011 mmol) andLindlar's catalyst (1.35 mg, 5% Pd) was stirred at room temperatureunder an atmosphere of H₂ for 28 hours. The suspension was filteredthrough silica gel (Et₂O rinse), concentrated in vacuo, and purified byflash chromatography over silica gel (40-60% CH₂Cl₂/hexane) to give 80(6.8 mg, 68%) as a colorless oil: [α]D²⁴ +3.6 (c 1.00, CHCl₃); IR (film)1743, 1699 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 6.91 (1H, s), 6.45 (1H, s),5.58 (1H, t, J=9.2 Hz), 5.2-5.35 (1H, m), 5.16 (1H, t, J=6.6 Hz), 4.39(1H, dd, J=3.1, 6.9 Hz), 4.09 (1H, t, J=6.6 Hz), 3.8-3.9 (1H, m),3.6-3.7 (1H, m); 3.66 (3H, s), 3.03 (1H, qn, J=6.7 Hz), 2.70 (3H, s),2.65-2.75 (2H, m), 2.3-2.5 (2H, m), 2.15-2.35 (3H, m), 1.99 (3H, s),1.64 (3H, s), 1.19 (3H, s), 1.06 (3H, s), 1.03 (3H, d, J=7.1 Hz), 1.00(3H, d, J=7.0 Hz), 0.92 (9H, s), 0.88 (9H, s), 0.86 (9H, s), 0.08 (3H,s), 0.07 (6H, s), 0.04 (3H, s), 0.00 (3H, s), −0.01 (3H, s); ¹³C NMR (75MHz, CDCl₃) δ 218.0, 172.6, 164.5, 153.4, 142.5, 135.5, 131.7, 128.7,122.2, 119.0, 115.2, 79.1, 76.1, 74.2, 53.5, 51.8, 46.4, 40.4, 37.9,35.6, 30.9, 26.4, 26.2, 26.0, 24.0, 23.9, 19.4, 19.3, 18.7, 18.4, 14.9,14.1, −3.3, −3.7, −4.3, −4.4, −4.7; HRMS (CI) calculated forC₄₆H₈₆O₆Si₃SN (M+H⁺) 864.5484, found 864.5510.

Example 27

This example describes the saponification of methyl ester 90 to formcarboxylic acid 80 as illustrated in Scheme 4. To a stirred solution ofthe methyl ester (51 mg, 59 μmol) in i-PrOH (1 mL) was added NaOH (11.5μL, 62 μmol, 5.4 M in H₂O), and the mixture was heated at 45° C. in asealed tube. After 16 hours, the solution was concentrated, diluted withaqueous HCl (20 mL, 0.5 M) and extracted with Et₂O (4×50 mL). The dried(Mg₂SO₄) extract was concentrated in vacuo and purified bychromatography over silica gel, eluting with 5-20% EtOAc/hexanes, togive acid 80 (33 mg, 34 μmol, 66%) as a colorless oil: IR (neat)3500-2500, 1713 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 6.93 (s, 1H), 6.67 (s,1H), 5.52 (t, J=9.6 Hz, 1H), 5.3-5.4 (m, 1H), 5.23 (t, J=7.4 Hz, 1H),4.41 (dd, J=3.3, 6.6 Hz, 1H), 3.75-3.85 (m, 1H), 2.9-3.1 (m, 2H), 2.71(s, 3H), 2.5-2.8 (m, 2H), 2.1-2.6 (m, 4H), 1.9-2.1 (m, 1H), 1.93 (s,3H), 1.71 (s, 3H), 1.16 (s, 3H), 1.13 (s, 3H), 1.04 (d, J=7.0 Hz, 3H),9.94 (obscured d, 3H), 0.92 (s, 9H), 0.88 (18H, s), 0.12 (s, 6H), 0.09(s, 3H), 0.06 (s, 3H), 0.03 (s, 3H), −0.01 (s, 3H); HRMS (CI) calculatedfor C₄₅H₈₄O₆Si₃SN (M+H⁺) 850.5327, found 850.5281.

Example 28

This example describes the deprotection of carboxylic acid 80 to formtriene 82 as illustrated in Scheme 4. To a stirred solution ofcarboxylic acid 80 (154 mg, 181 μmol) in THF (3.9 mL) at 0° C. was addedTBAF (1.1 mL, 1.1 mmol, 1 M in THF). The solution was allowed to warmslowly to room temperature overnight. After 16 hours, the mixture wasdiluted with EtOAc, washed with saturated aqueous NH₄Cl (50 mL), andextracted with EtOAc (4×100 mL). The dried (Mg₂SO₄) extract wasconcentrated in vacuo and purified by chromatography over silica gel,eluting with 2-5% MeOH/CH₂Cl₂, to give 82 (118.5 mg, 160 μmol, 89%) as awhite foam: [α]D²³ −2.6 (c 3.50, CHCl₃); IR (neat) 3500-2500, 1709 cm⁻¹;¹H NMR (300 MHz, CDCl₃) δ 6.95 (s, 1H), 6.70 (s, 1H), 5.56 (t, J=10.0Hz, 1H), 5.3-5.45 (m, 1H), 5.24 (t, J=7.3 Hz, 1H), 4.35-4.45 (m, 1H),4.16 (t, J=6.2 Hz, 1H), 3.75-3.85 (m, 1H), 3.03 (m, 2H), 2.75-2.85 (m,1H), 2.72 (s, 3H), 2.65-2.75 (m, 1H), 2.2-2.7 (m, 5H), 1.99 (s, 3H),1.74 (s, 3H), 1.15 (s, 3H), 1.14 (s, 3H), 1.04 (d, J=7.1 Hz, 3H), 0.98(d, J=6.9 Hz, 3H), 0.92 (s, 9H), 0.87 (s, 9H), 0.12 (s, 3H), 0.10 (s,3H), 0.07 (s, 3H), 0.06 (s, 3H); ¹³C NMR (75 MHz, CDCl₃) δ 218.1, 176.0,165.1, 152.4, 141.9, 137.5, 131.6, 127.8, 120.8, 118.8, 115.1, 77.2,76.0, 73.5, 53.6, 46.3, 40.1, 38.0, 34.1, 30.8, 26.2, 26.0, 23.7, 23.5,19.0, 18.9, 18.7, 18.5, 18.1, 15.0, 14.6, −3.6, −4.1, −4.2, −4.6; HRMS(CI) calculated C₃₉H₇₀O₆Si₂SN (M+H⁺) 736.4462, found 736.4451.

Example 29

This example describes the synthesis of compound 94. To a stirredsolution of 92 (195 mg, 0.32 mmol) in THF (1.5 mL) was added2-(trimethylsilyl)ethanol (69 μL, 0.48 mmol) and triphenylphosphine(56.8 mg, 0.80 mmol). The solution was cooled to 0° C. and diethylazodicarboxylate was added. After 1.5 hours, the reaction was quenchedwith saturated aqueous NH₄Cl, and the solution was extracted with Et₂O.The extract was concentrated in vacuo, and the residue was purified bychromatography on silica gel, eluting with 5-10% Et₂O/petroleum ether,to give 94 (175 mg, 75% ) as a colorless oil: [α]D²³ −27.0 (c 1.03,CHCl₃; IR (neat) 1741, 1690 cm⁻¹; ¹H NMR (300 MHz, CDCl₁₃) δ 7.23 (d,J=8.4 Hz, 2H), 6.85 (d, J=8.4 Hz, 2H), 4.39 (s, 2H), 4.3-4.4 (m, 1H),3.83 (d, J=7.8 Hz, 1H), 3.58 (dd, J=5.7, 9.1 Hz, 1H), 3.31 (dq, J=7.2,7.2 Hz, 1H), 3.18 (dd, J=7.3, 9.1 Hz, 1H), 2.46 (dd, J=3.1, 16.1 Hz,1H), 2.26 (dd, J=7.0, 16.1 Hz, 1H), 1.7-1.85 (m, 1H), 1.14 (s, 3H), 1.06(s, 3H), 1.01 (d, J=6.9 Hz, 3H), 0.95 (d, J=6.9 Hz, 3H), 0.88 (s, 9H),0.87 (s, 9H), 0.08 (s, 3H), 0.05 (s, 6H), 0.02 (s, 3H); ¹³C NMR (CDCl3)δ 218.5, 172.7, 159.3, 131.0, 129.5, 113.9, 74.1, 73.1, 71.8, 55.5,53.6, 51.8, 46.3, 40.4, 38.9, 29.9, 26.5, 26.2, 24.0, 18.8, 18.7, 18.4,17.0, 15.7, −3.3, −3.5, −4.3, −4.4; HRMS (CI) calcd. for C₃₈H₇₃O₇Si(M+H⁺) 725.4664, found 725.4666.

Example 30

This example describes the synthesis of compound 95. To a stirredsolution of 94 (150 mg, 0.20 mmol) in EtOH (4.0 mL) was addedpalladium-on-carbon (55 mg, 10% Pd), and the mixture was stirred underan atmosphere of H₂. After 1 hours, the H₂ atmosphere was replaced byAr, and the mixture was filtered through Celite (EtOH rinse). Thefiltrate was concentrated in vacuo, and the residue was purified bychromatography on silica gel, eluting with 10-30% Et₂O/petroleum ether,to give 95 (108 mg, 89%) as a colorless oil: [α]D²³ −8.47 (c 1.18,CHCl₃); IR (neat) 3538, 1743, 1694 cm⁻¹; ¹H NMR (300 MHz, CDCl3) δ 4.40(dd, J=2.9, 6.9 Hz, 1H), 4.17-4.11 (m, 2H) 3.93 (dd, J=2.0, 7.8 Hz, 1H),3.6-3.7 (m, 1H), 3.5-3.6 (m, 1H), 3.31 (dq, J=7.5, 7.5 Hz, 1H), 2.43(dd, J=2.7, 16.3 Hz, 1H), 2.26 (1H, dd, J=6.9, 16.3 Hz), 1.55-1.65 (1H,m), 1.22 (3H, s), 1.13 (3H, s), 1.09 (d, J=7.0 Hz, 3H), 0.95 (d, J=7.1Hz, 3H), 0.92 (s, 9H), 0.87 (s, 9H), 0.85 (m, 2H), 0.02 (s, 9H) 0.12 (s,3H), 0.10 (s, 3H), 0.09 (s, 3H), 0.01 (s, 3H); ¹³C NMR (CDCl₃) δ 218.4,172.8, 78.2, 73.6, 64.9, 60.3, 53.9, 51.9, 47.0, 40.3, 39.8, 29.9, 26.4,26.2, 24.1, 19.1, 18.6, 18.4, 17.2 16.1, −3.0, −3.4, −3.6, −4.3, −4.4.

Example 31

This example describes the synthesis of compound 96. To a stirredmixture of 95 (200 mg, 0.33 mmol) and powdered molecular sieves (300 mg)in CH₂Cl₂ (6.0 mL) was added sequentially N-methylmorpholine-N-oxide (97mg, 0.83 mmol) followed by tetra-n-propylammonium perruthenate (11.6 mg,33 μmol). After 1.5 hours, the mixture was filtered through silica (Et₂Orinse), and the filtrate was concentrated in vacuo to give the crudealdehyde as a colorless oil.

To a stirred solution of the crude aldehyde and K₂CO₃ (91 mg, 0.66 mmol)in MeOH (5.0 mL) was added dimethyl 1-diazo-2-oxopropylphosphonate (74mg, 0.46 mmol). The solution was stirred for 4 hours at roomtemperature, diluted with Et₂O (30 mL), washed with aqueous NaHCO₃ (5%),and extracted with Et₂O (3×30 mL). The dried (Mg₂SO₄) extract wasconcentrated in vacuo, and the residue was purified by flashchromatography on silica gel, eluting with 2% Et₂O/hexanes, to give 96(155 mg, 78%) as a colorless oil: [α]D²³ −25.1 (c 2.50, CHCl₃); IR(neat) 2946, 2928, 2848, 1734, 1690, 1468; ¹H NMR (300 MHz, CDCl₃) δ4.45 (dd, J=3.1, 7.5 Hz, 1H), 4.11-4.16 (m, 2H), 3.76 (dd, J=2.1, 6.4Hz, 1H), 3.35 (dq, J=7.3, 7.3 Hz, 1H), 2.22-2.24 (m, 3H), 2.06 (s, 1H),1.25 (s, 3H), 1.18 (d, J=7.5 Hz, 3H), 1.17 (s, 3H), 1.07 (d, J=6.8 Hz,3H), 0.95 (obscured m, 2H) 0.92 (s, 9H), 0.86 (s, 9H), 0.10 (s, 3H),0.07 (s, 3H), 0.07 (s, 3H), 0.03 (s, 9H), 0.02 (s, 3H); ¹³C NMR (75 MHz,CDCl₃) δ 218.6, 172.1, 85.6, 75.7, 73.3, 70.8, 62.7, 53.8, 46.5, 40.6,32.2, 26.1, 26.0, 18.7, 18.5, 18.2, 17.2, 15.9, −1.6, −3.3, −3.9, −4.4,−4.7; HRMS (FAB) calcd. for C₅₁H₆₃O₅Si₃ (M+H⁺) 599.3983, found 599.3982.

Example 32

This example describes the synthesis of compound 98. To a stirredsolution of 96 (60.0 mg, 0.10 mmol) and bis(triphenylphosphine)palladiumdichloride (1.4 mg, (0.002 mmol) in THF (0.5 mL) at room temperature wasadded slowly tri-n-butyltin hydride (32.3 μL, 0.12 mmol). After 10minutes, the solution was concentrated in vacuo, and the residue waspurified by chromatography on silica gel, eluting with 5% Et₂O/hexanes,to give 98 (79 mg, 89%) as a colorless oil: [α]D²³ −9.6 (c 1.35, CHCl₃);IR (neat) 2955, 2928, 2856, 1736, 1472 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ6.12 (dd, J=7.5, 19.3 Hz, 1H), 5.89 (d, J=19.3 Hz, 1H), 4.43 (dd, J=3.2,6.8 Hz, 1H), 4.15 (m, 2H), 3.85 (dd, J=1.5, 7.9 Hz, 1H), 3.07 (dq,J=7.1, 7.1 Hz, 1H), 2.40 (dd, J=3.2, 16.2 Hz, 1H), 2.23 (dd, J=6.8, 16.2Hz, 1H), 1.45-1.53 (m, 6H), 1.23-1.37 (m, 12H), 1.19 (s, 3H), 1.09 (s,3H), 1.03 (d, J=7.0, 3H), 1.03 (d, J=6.9, 3H), 0.93 (s, 9H), 0.87 (s,9H), 0.85-0.93 (m, 12H), 0.10 (s, 3H), 0.09 (s, 3H), 0.08 (s, 3H), 0.04(s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 218.8, 172.6, 150.7, 129.1, 74.0,63.1, 53.9, 47.5, 47.1, 41.0, 29.6, 27.7, 26.6, 26.4, 24.5, 19.2, 18.9,17.7, 15.9, 14.1, 9.9, −1.1, −2.9, −3.4, −4.0, −4.3.

Example 33

This example describes the synthesis of compound 102. To a stirredsolution of 100 (1.00 g, 2.48 mmol) in CH₂Cl₂ (25 mL) at −78° C. wasadded 2,6-lutidine (61 mg, 0.66 mL, 5.72 mmol). After 4 minutes,triethylsilyl triflate (1.19 g, 1.0 mL, 4.5 mmol) was added to the coldsolution, and after 30 minutes the reaction was quenched with saturatedaqueous NH₄Cl (60 mL) and extracted with Et₂O (3×100 mL). The dried(Mg₂SO₄) extract was concentrated in vacuo and the residue was purifiedby chromatography on silica gel, eluting with 30-50% Et₂O/hexane, togive 102 (1.00 g, 78%) as a colorless oil: [α]D²³ +31.2 (c 1.63, CHCl₃);IR (neat) 1782, 1714 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 7.15-7.4 (m, 5H),5.35-5.5 (m, 2H), 4.55-4.7 (m, 2H), 4.05-4.2 (m, 2H), 4.0-4.15 (m, 2H),3.8-3.9 (m, 1H, of a diastereomer), 3.4-3.5 (m, 1H of a diastereomer),3.36 (d, J=13.1 Hz, 1H of a diastereomer), 2.7-2.8 (m, 1H of adiastereomer), 2.45-2.55 (m, 2H), 2.46 (q, J=7.3 Hz, 1H), 1.5-1.8 (m,9H), 0.97 (t, J=7.8 Hz, 9H), 0.62 (q, J=7.6Hz, 6H); ¹³C NMR (75 MHz,CDCl₃) δ 173.9, 173.7, 153.3, 135.5, 134.9, 129.6, 129.1, 127.5, 124.0,97.6, 96.9, 71.1, 66.7, 65.5, 65.2, 62.3, 61.9, 55.8, 37.9, 34.2, 33.7,30.8, 30.7, 26.0, 25.7, 22.0, 21.9, 19.7, 19.4, 18.5, 6.7, 5.1; HRMS(CI) calcd. for C₂₈H₄₄NO₆Si (M+H⁺) 518.2938, found 518.2908.

Example 34

This example describes the synthesis of compound 104. To a stirredsolution of ethanethiol (361 mg, 430 μL, 5.82 mmol) in THF (25 mL) atroom temperature was added KH (55 mg, 0.48 mmol, 35% in mineral oil).After 30 minutes, the mixture was cooled to 0° C. and a solution of 102(1.00 g, 1.94 mmol) in THF (10 mL) was added via cannula during 5minutes. An additional amount of THF (5 mL) was added, and after 1 hourat room temperature the reaction was quenched with saturated aqueousNH₄Cl (25 mL). Air was passed through the solution for 2 hours to removeexcess ethanethiol, and the mixture was extracted with Et₂O (3×100 mL).The dried (Mg₂SO₄) extract was concentrated in vacuo and the residue wastaken up in 10% Et₂O/petroleum ether, from which4-benzyloxazolidin-2-one crystallized as a colorless solid. The decantedsolution was concentrated and the residue was purified by chromatographyon silica gel, eluting with 30% Et₂O/hexane, to give the thioester (730mg, 97%) as a colorless oil: [α]D²³ −16.8 (c 2.73, CHCl₃); IR (neat)1684 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 5.35-5.5 (m, 1H), 4.55 (bs, 1H),3.9-4.2 (m, 3H), 3.8-3.9 (m, 1H), 3.45-3.6 (m, 1H), 3.36 (d, J=13.1 Hz,1H), 2.75-2.9 (m, 2H), 2.4-2.6 (m, 2H), 1.4-1.9 (m, 6H), 1.21 (t, J=7.5Hz, 3H), 0.97 (t, J=7.8 Hz, 9H), 0.62 (q, J=7.8 Hz, 6H); ¹³C NMR (75MHz, CDCl₃) δ 205.1, 205.0, 135.24, 135.16, 97.9, 97.4, 78.6, 65.7,65.5, 62.3, 62.2, 34.5, 30.8, 25.9, 25.7, 22.6, 22.1, 22.0, 19.7, 19.6,18.4, 14.8, 6.7, 5.1; HRMS (CI) calcd. for C₂₀H₃₇NO₄SSi (M+H⁺) 401.2182,found 401.2172

To a stirred solution of CuI (2.60 g, 13.67 mmol) in Et₂O (120 mL) at 0°C. was added MeLi (17.8 mL, 24.9 mmol, 1.4M in Et₂O). The mixture wascooled to −50° C. and a solution of the thioester (960 mg, 2.49 mmol) inEt₂O (50 mL) was added via cannula. An additional amount of Et₂O (5 mL)was added to rinse the flask. After 30 minutes, the reaction wasquenched with saturated aqueous NH₄Cl (200 mL), and the mixture wasextracted with Et₂O (3×120 mL). The dried (Mg₂SO₄) extract wasconcentrated in vacuo and the residue was purified by chromatography onsilica gel, eluting with 15% Et₂O/hexane, to give the methyl ketone (548mg, 62%) as a colorless oil: [α]D²³ −11.0 (c 3.26, CHCl₃); IR (neat)1719 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 5.35-5.5 (m, 5H), 4.5-4.55 (m, 1H),3.9-4.1 (m, 3H), 3.75-3.9 (m, 1H), 3.4-3.5 (m, 1H), 2.3-2.5 (m, 2H),2.10 (s, 3H) 1.4-1.9 (m, 6H), 0.97 (t, J=7.8 Hz, 9H), 0.62 (q, J=7.8 Hz,6H); ¹³C NMR (75 MHz, CDCl₃) δ 211.7, 135.2, 135.1, 123.8, 123.5, 97.7,97.3, 79.0, 65.5, 65.2, 62.2, 62.1, 33.2, 30.7, 25.8, 25.6, 25.5, 22.0,19.6, 19.5, 18.2, 6.7, 5.1; HRMS (CI) calcd. for C₁₉H₃₇O₄Si (M+H⁺)357.2461, found 357.2455.

To a stirred solution of 53 (1.26 g, 5.08 mmol) in THF (9 mL) at −78° C.was added n-BuLi (4.7 mL, 5.00 mmol, 1.2 M in hexanes), and after 20minutes, a solution of the methyl ketone (520 mg, 1.45 mmol) in THF (6mL) was added via cannula. An additional amount of THF (2 mL) was addedto rinse the flask. After 30 minutes, the solution was allowed to warmslowly to room temperature during 1 hour, then was cooled at −78° C. foran additional 30 minutes before the reaction was quenched with saturatedaqueous NH₄Cl (50 mL). The mixture was extracted with Et₂O (3×65 mL),and the dried (Mg₂SO₄) extract was concentrated in vacuo. The residuewas purified by chromatography on silica gel, eluting with 20%Et₂O/hexanes, to give the thiazole (627 mg, 96%) as a colorless oil:[α]D²³ −33.9 (c 2.56, CHCl₃); IR (neat) 2950, 1512, 1455 cm⁻¹; ¹H NMR(300 MHz, CDCl₃) δ 6.91 (s, 1H), 6.45, (s, 1H), 5.35-5.5 (m, 1H),4.5-4.6 (m, 1H), 3.9-4.2 (m, 3H), 3.8-3.9 (m, 1H), 3.45-3.6 (m, 1H),2.70 (s, 3H), 2.2-2.4 (m, 2H), 1.99 (d, J=1.0 Hz, 3H), 1.4-1.9 (m, 6H),0.92 (t, J=7.9 Hz, 9H), 0.72 (q, J=7.9 Hz, 6H); ¹³C NMR (75 MHz, CDCl₃)δ 164.2, 153.1, 142.5, 142.2, 133.4, 125.6, 125.5, 118.7, 118.6, 114.9,97.4, 97.2, 78.4, 77.3, 65.4, 65.3, 62.0, 61.9, 35.0, 34.9, 30.6, 25.4,21.7, 19.4, 19.4, 19.1, 13.8, 6.7, 4.7; HRMS (CI) calcd. forC₂₄H₄₂NO₃SSi (M+H⁺) 452.2655, found 452.2645.

To a stirred solution of freshly prepared MgBr₂ (631 mg, 26.2 mmol ofMg, and 2.38 mL, 27.7 mmol, of 1,2-dibromoethane) in Et₂O (50 mL) atroom temperature was added the thiazole (556 mg, 1.20 mmol) in Et₂O (5mL) followed by saturated aqueous NH₄Cl (approx 50 μL). After 3.5 hours,the mixture was cooled to 0° C. and carefully quenched with saturatedaqueous NH₄Cl (50 mL). The mixture was extracted with Et₂O (3×100 mL),and the dried (Mg₂SO₄) extract was concentrated in vacuo. The residuewas purified by chromatography on silica gel, eluting with 30%Et₂O/hexanes, to give 104 (390 mg, 89%) as a colorless oil: [α]D²³ −31.0(c 2.74); IR (neat) 3374 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 6.92 (s, 1H),6.44, (s, 1H), 5.31 (t, J=7.7 Hz, 1H), 4.14 (d, J=12.2 Hz, 1H), 4.1-4.2(m, 1H), 4.00 (d, J=12.2 Hz, 1H), 2.71 (s, 3H), 2.4-2.5 (m, 1H), 2.2-2.3(m, 2H), 2.00 (s, 3H), 1.80 (s, 3H), 0.92 (t, J=7.9 Hz, 9H), 0.72 (q,J=7.9 Hz, 6H); ¹³C NMR (75 MHz, CDCl₃) δ 164.8, 153.0, 142.4, 137.7,124.4, 119.0, 115.4, 78.4, 62.0, 61.9, 35.5, 29.9, 26.0, 22.2, 19.3,18.5, 14.3, 6.7, 4.7; HRMS (CI) calcd. for C₁₉H₃₄NO₂SSi (M+H⁺) 368.2080,found 368.2061.

Example 35

This example describes the synthesis of compound 106. To a stirredsolution of 104 (35 mg, 95 μmol) in CH₂Cl₂ (0.6 mL) at 0° C. was addedEt₃N (23 μL, 161 μmol) followed by methanesulfonic anhydride (21 mg, 119μmol). After 10 minutes, acetone (0.6 mL) was added followed by LiCl (40mg, 950 μmol). After 4 hours at room temperature, the solution wasconcentrated in vacuo to remove acetone, diluted with saturated aqueousNH₄Cl, and extracted with Et₂O. The dried (Mg₂SO₄) extract wasconcentrated in vacuo and the residue was purified by chromatography onsilica gel, eluting with 10-20% Et₂O/petroleum ether, to give 106 (36mg, 97%) as a colorless oil: [α]D²³ +28.1 (c 1.11; CHCl₃); IR (neat)2954, 2875, 1453, 1072 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 6.94 (s, 1H),6.49 (s, 1H), 5.41 (dt, J=1.3, 7.5 Hz, 1H), 4.15 (m, 1H), 4.14 (d,J=10.8, 1H), 4.00 (d, J=10.8, 1H), 2.71 (s, 3H), 2.35 (m, 2H), 2.01 (d,J=1.2, 3H), 1.75 (d, J=1.2, 3H), 0.93 (t, J=7.69, 9H), 0.58 (q, J=7.39,6H); ¹³C NMR (75 MHz, CDCl₃) δ 164.5, 153.5, 142.3, 133.4, 127.8, 119.4,115.6, 78.4, 44.2, 35.8, 22.1, 19.6, 14.4, 7.2, 5.2; HRMS (FAB) calcd.for C₁₉H₃₃ClNOSSi (M+H⁺) 386.1741, found 386.1737.

Example 36

This example describes the synthesis of compound 108. A solution of 106(44 mg, 114 μmol), tris(dibenzylideneactone)dipalladium-chloroform (7.1mg, 6.8 μmol) and triphenylarsine (8.4 mg, 27 μmol) in THF (0.4 mL) wasstirred at room temperature for 10 minutes solution of 98 (107 mg, 120μmol) in THF (1.0 mL) was added, and the flask was briefly opened to theatmosphere, resealed, and heated to 65° C. After 18 hours, mixture wasconcentrated in vacuo and the residue was purified by chromatography onsilica gel, eluting with 5% Et₂O/hexanes, to give 108 (82 mg, 76%) as acolorless oil: [α]D²³ −6.2 (c 1.23, CHCl₃); IR (neat) 2955, 2856, 753,1694, 1471 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 6.91(s, 1H), 6.47 (s, 1H),5.52 (dd, J=7.9, 15.6 Hz, 1H), 5.32 (dt, J=6.7, 8.5 Hz, 1H), 5.17 (t,J=7.3, 1H), 4.40 (dd, J=3.1, 6.7 Hz, 1H), 4.15-4.18 (m, 2H), 3.82 (dd,J=1.8, 7.2, 1H), 3.02 (dq, J=7.1, 7.1 Hz, 1H), 2.72 (s, 3H), 2.66 (d,J=6.6 Hz, 2H), 2.20-2.44 (m, 3H), 2.00 (s, 3H), 1.26 (s, 3H), 1.07 (s,3H), 1.01 (d, J=7.0 Hz, 3H), 1.00 (d, J=6.0 Hz, 3H), 0.93 (t, J=7.8 Hz,9H), 0.91 (s, 9H), 0.87 (s, 9H), 0.58 (q, J=7.8 Hz, 6H), 0.10 (s, 3H),0.06 (s, 3H), 0.03 (s, 3H), 0.03 (s, 9H), 0.02 (s, 3H); ¹³C NMR (75 MHz,CDCl₃) δ 218.5, 172.6, 164.7, 153.6, 143.0, 136.0, 133.1, 129.7, 121.9,119.0, 115.3, 79.0, 76.8, 63.1, 53.8, 46.6, 43.8, 42.8, 40.9, 26.6,26.4, 19.6, 18.9, 18.6, 17.7, 16.7, 14.4, 7.3, 5.5, −1.1, −3.1, −3.4,−4.0, −4.2; HRMS (FAB) calcd. for C₅₀H₉₆NO₆SSi₄ (M+H⁺) 950.6036, found950.6065.

Example 37

This example describes the synthesis of compound 110. To a stirredsolution of 108 (20 mg, 21 μmol) and powdered molecular sieves (100 mg)in THF (8.0 mL) at 0° C. was added tetra-n-butylammonium fluoride (16.5mg, 63 μmol). After 6 hours, the mixture was filtered through glasswool, and aqueous citric acid (pH 5, 8 mL) was added to the filtrate,which was extracted with Et₂O. The dried (Mg₂SO₄) extract wasconcentrated in vacuo and the residue was purified by flashchromatography on silica gel, eluting with 4% MeOH/CH₂Cl₂, to give 110(12.8 mg, 83%) as a colorless oil: [α]D²³ −22.4 (c 2.15, CHCl₃); IR(neat) 3252, 2956, 2929, 2856, 1712 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 6.96(s, 1H), 6.58, (s, 1H), 5.54 (dd, J=7.5, 15.2 Hz, 1H), 5.38 (dt, J=6.7,15.2 Hz, 1H), 5.20 (t, J=7.8 Hz, 1H), 4.40 (dd, J=3.2, 6.4 Hz, 1H),4.16-4.24 (m, 1H), 3.83-3.86 (m, 1H), 3.02-3.09 (m, 1H), 2.72 (s, 3H),2.69-2.72 (m, 2H), 2.28-2.55 (m, 5H), 1.98-2.08 (m, 2H), 2.03 (s, 3H),1.63 (s, 3H), 1.17 (s, 3H), 1.12 (s, 3H), 1.04 (d, J=6.9 Hz, 3H), 0.97(d, J=6.9 Hz, 3H), 0.92 (s, 9H), 0.89 (s, 9H), 0.11 (s, 3H), 0.07 (s,3H), 0.07 (s, 3H), 0.06 (s, 3H) ); ¹³C NMR (75 MHz, CDCl₃) δ 218.8,175.9, 165.4, 153.0 142.1, 138.2, 133.3, 129.5, 120.6, 119.4, 115.7,76.9, 76.7, 73.7, 54.0, 46.8, 43.6, 42.8, 40.4, 34.6, 30.1, 26.6, 26.4,24.2, 20.1, 19.3, 18.9, 18.6, 16.9, 14.7, −3.1, −3.5, −3.7, −4.2; HRMS(FAB) calcd. for C₃₉H₇₀NO₆SSi₂ (M+H⁺) 736.4462, found 736.4466.

Example 38

This example describes the synthesis of compound 112. To a stirredsolution of 110 (22.0 mg, 30.0 μmol) in THF (0.5 mL) at 0° C. was addedEt₃N (7.6 μL, 54 μmol) followed by 2,4,6-trichlorobenzoyl chloride (5.6μL, 36 μmol). After 45 minutes, the mixture was diluted with THF (0.4mL) and toluene (0.7 mL), and was added via syringe pump to a stirredsolution of DMAP (6.5 mg, 53 μmol) in toluene (7.2 mL) at 75° C. during3.5 h. After an additional 1 hour, the solution was allowed to cool toroom temperature, diluted with EtOAc, washed with saturated aqueousNH₄Cl (20 mL), and extracted with EtOAc (4×40 mL). The dried (Mg₂SO₄)extract was concentrated in vacuo and the residue was purified bychromatography on silica gel, eluting with 5% EtOAc/hexanes, to give 112(19.4 mg, 71%) as a colorless oil: [α]D²³ −2.12 (c 1.13, CHCl₃); IR(neat) 2929, 2856, 1735, 1700 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 6.94 (s,3H), 6.54 (s, 3H), 5.44-5.46 (m, 2H), 5.28 (m, 1H), 5.22 (dd, J=3.3,9.7, 1H), 4.63 (dd, J=3.2, 8.7, 1H), 3.90 (m, 1H), 3.16 (dq, J=6.8, 6.8Hz, 1H), 2.71 (s, 3H), 2.20-2.71 (m, 6H), 2.14 (s, 3H), 1.68 (s, 3H),1.10 (d, J=6.8 Hz, 3H), 1.10 (s, 3H), 1.07 (s, 3H), 1.04 (d, J=7.0, 1H),0.93 (s, 9H), 0.85 (s, 9H), 0.11 (s, 3H), 0.11 (s, 3H), 0.10 (s, 3H),0.88 (s, 3H); ¹³C NMR (100 MHz, CDCl₃) δ 215.9, 170.7, 165.1, 153.1,138.7, 137.8, 133.9, 128.3, 120.3, 119.8, 116.8, 80.8, 77.7, 73.3, 55.1,44.1, 43.1, 42.3, 42.0, 32.8, 26.6, 26.4, 21.2, 19.7, 19.1, 18.9, 18.2,18.0, 17.2, 15.2, −2.5, −3.4, −3.8, −3.8; HRMS (FAB) calcd. forC₃₉H₆₈NO₅SSi₂ (M+H⁺) 718.4357, found 718.4345.

Example 39

This example describes the synthesis of compound 114. To a stirredsolution of 112 (14.5 mg, 20 μmol) in CH₂Cl₂ (125 μL) at 0° C. was addedtrifluoroacetic acid (112 μL). After 8 hours, the mixture wasconcentrated in vacuo, and the residue was purified by chromatography onsilica gel, eluting with 20-50% EtOAc/hexanes, to give 114 (9.3 mg, 19μmol, 95%) as a colorless waxy solid: [α]D²³ −35.4 (c 0.50, CHCl₃); IR(neat) 2971, 2927, 1729, 1691 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 6.98 (s,1H), 6.55 (s, 1H), 5.53-5.48 (m, 2H), 5.38 (dd, J=2.8, 9.4 Hz, 1H), 5.23(m, 1H), 4.23 (dd, J=4.3, 8.2 Hz, 1H), 3.71 (m, 1H), 3.27 (dq, J=5.8,6.7 Hz, 1H), 2.27-2.77 (m, 6H), 2.72 (s, 3H), 2.11 (s, 3H), 1.69 (s,3H), 1.26 (s, 3H), 1.17 (d, J=6.8 Hz, 3H), 1.10 (d, J=7.0 Hz, 3H), 1.05(s, 3H); ¹³C NMR (75 MHz, CDCl₃) δ 219.7, 171.0, 165.2, 152.7, 138.4,137.8, 132.8, 129.6, 120.4, 120.2, 116.6, 79.2, 77.0, 76.4, 74.6, 72.3,53.3, 44.7, 42.9, 40.3, 39.5, 32.6, 21.6, 20.0, 19.6, 17.8, 17.1, 15.9,15.2; HRMS (FAB) calcd. for C₂₇H₄₀NO₃S (M+H⁺) 490.2627, found 490.2634.

The present invention has been described in accordance with workingembodiments; however, it will be understood that certain modificationsmay be made thereto without departing from the invention. We claim asour invention the preferred embodiment and all such modifications andequivalents as come within the true spirit and scope of the followingclaims.

1-56. (canceled)
 57. A compound having the formula